diff --git a/automotive/vehicle/aidl/impl/utils/common/include/VehicleHalTypes.h b/automotive/vehicle/aidl/impl/utils/common/include/VehicleHalTypes.h
index 013d177..a7fcdcf 100644
--- a/automotive/vehicle/aidl/impl/utils/common/include/VehicleHalTypes.h
+++ b/automotive/vehicle/aidl/impl/utils/common/include/VehicleHalTypes.h
@@ -37,6 +37,7 @@
 #include <aidl/android/hardware/automotive/vehicle/SetValueResult.h>
 #include <aidl/android/hardware/automotive/vehicle/SetValueResults.h>
 #include <aidl/android/hardware/automotive/vehicle/StatusCode.h>
+#include <aidl/android/hardware/automotive/vehicle/SubscribeOptions.h>
 #include <aidl/android/hardware/automotive/vehicle/VehicleApPowerStateReport.h>
 #include <aidl/android/hardware/automotive/vehicle/VehicleApPowerStateReq.h>
 #include <aidl/android/hardware/automotive/vehicle/VehicleArea.h>
diff --git a/automotive/vehicle/aidl/impl/vhal/Android.bp b/automotive/vehicle/aidl/impl/vhal/Android.bp
index eaa23dc..0132e6f 100644
--- a/automotive/vehicle/aidl/impl/vhal/Android.bp
+++ b/automotive/vehicle/aidl/impl/vhal/Android.bp
@@ -58,6 +58,7 @@
         "src/DefaultVehicleHal.cpp",
         "src/PendingRequestPool.cpp",
         "src/RecurrentTimer.cpp",
+        "src/SubscriptionManager.cpp",
     ],
     static_libs: [
         "VehicleHalUtils",
diff --git a/automotive/vehicle/aidl/impl/vhal/include/SubscriptionManager.h b/automotive/vehicle/aidl/impl/vhal/include/SubscriptionManager.h
new file mode 100644
index 0000000..28809c6
--- /dev/null
+++ b/automotive/vehicle/aidl/impl/vhal/include/SubscriptionManager.h
@@ -0,0 +1,151 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef android_hardware_automotive_vehicle_aidl_impl_vhal_include_SubscriptionManager_H_
+#define android_hardware_automotive_vehicle_aidl_impl_vhal_include_SubscriptionManager_H_
+
+#include "RecurrentTimer.h"
+
+#include <VehicleHalTypes.h>
+
+#include <aidl/android/hardware/automotive/vehicle/IVehicleCallback.h>
+#include <android-base/result.h>
+#include <android-base/thread_annotations.h>
+
+#include <mutex>
+#include <unordered_map>
+#include <unordered_set>
+#include <vector>
+
+namespace android {
+namespace hardware {
+namespace automotive {
+namespace vehicle {
+
+// A thread-safe subscription manager that manages all VHAL subscriptions.
+class SubscriptionManager final {
+  public:
+    using CallbackType =
+            std::shared_ptr<::aidl::android::hardware::automotive::vehicle::IVehicleCallback>;
+    using GetValueFunc = std::function<void(
+            const CallbackType& callback,
+            const ::aidl::android::hardware::automotive::vehicle::VehiclePropValue& value)>;
+
+    explicit SubscriptionManager(GetValueFunc&& action);
+    ~SubscriptionManager();
+
+    // Subscribes to properties according to {@code SubscribeOptions}. Note that all option must
+    // contain non-empty areaIds field, which contains all area IDs to subscribe. As a result,
+    // the options here is different from the options passed from VHAL client.
+    // Returns error if any of the subscribe options is not valid. If error is returned, no
+    // properties would be subscribed.
+    // Returns ok if all the options are parsed correctly and all the properties are subscribed.
+    ::android::base::Result<void> subscribe(
+            const CallbackType& callback,
+            const std::vector<::aidl::android::hardware::automotive::vehicle::SubscribeOptions>&
+                    options,
+            bool isContinuousProperty);
+
+    // Unsubscribes from the properties for the callback.
+    // Returns error if the callback was not subscribed before or one of the given property was not
+    // subscribed. If error is returned, no property would be unsubscribed.
+    // Returns ok if all the requested properties for the callback are unsubscribed.
+    ::android::base::Result<void> unsubscribe(const CallbackType& callback,
+                                              const std::vector<int32_t>& propIds);
+
+    // Unsubscribes to all the properties for the callback.
+    // Returns error if the callback was not subscribed before. If error is returned, no property
+    // would be unsubscribed.
+    // Returns ok if all the properties for the callback are unsubscribed.
+    ::android::base::Result<void> unsubscribe(const CallbackType& callback);
+
+    // For a list of updated properties, returns a map that maps clients subscribing to
+    // the updated properties to a list of updated values. This would only return on-change property
+    // clients that should be informed for the given updated values.
+    std::unordered_map<
+            std::shared_ptr<::aidl::android::hardware::automotive::vehicle::IVehicleCallback>,
+            std::vector<const ::aidl::android::hardware::automotive::vehicle::VehiclePropValue*>>
+    getSubscribedClients(
+            const std::vector<::aidl::android::hardware::automotive::vehicle::VehiclePropValue>&
+                    updatedValues);
+
+    // Checks whether the sample rate is valid.
+    static bool checkSampleRate(float sampleRate);
+
+  private:
+    struct PropIdAreaId {
+        int32_t propId;
+        int32_t areaId;
+
+        bool operator==(const PropIdAreaId& other) const;
+    };
+
+    struct PropIdAreaIdHash {
+        size_t operator()(const PropIdAreaId& propIdAreaId) const;
+    };
+
+    // A class to represent a registered subscription.
+    class Subscription {
+      public:
+        Subscription() = default;
+
+        Subscription(const Subscription&) = delete;
+
+        virtual ~Subscription() = default;
+
+        virtual bool isOnChange();
+    };
+
+    // A subscription for OnContinuous property. The registered action would be called recurrently
+    // until this class is destructed.
+    class RecurrentSubscription final : public Subscription {
+      public:
+        explicit RecurrentSubscription(std::shared_ptr<RecurrentTimer> timer,
+                                       std::function<void()>&& action, int64_t interval);
+        ~RecurrentSubscription();
+
+        bool isOnChange() override;
+
+      private:
+        std::shared_ptr<std::function<void()>> mAction;
+        std::shared_ptr<RecurrentTimer> mTimer;
+    };
+
+    // A subscription for OnChange property.
+    class OnChangeSubscription final : public Subscription {
+      public:
+        bool isOnChange() override;
+    };
+
+    mutable std::mutex mLock;
+    std::unordered_map<PropIdAreaId, std::unordered_set<CallbackType>, PropIdAreaIdHash>
+            mClientsByPropIdArea GUARDED_BY(mLock);
+    std::unordered_map<CallbackType, std::unordered_map<PropIdAreaId, std::unique_ptr<Subscription>,
+                                                        PropIdAreaIdHash>>
+            mSubscriptionsByClient GUARDED_BY(mLock);
+    // RecurrentTimer is thread-safe.
+    std::shared_ptr<RecurrentTimer> mTimer;
+    const GetValueFunc mGetValue;
+
+    static ::android::base::Result<int64_t> getInterval(float sampleRate);
+};
+
+}  // namespace vehicle
+}  // namespace automotive
+}  // namespace hardware
+}  // namespace android
+
+#endif  // android_hardware_automotive_vehicle_aidl_impl_vhal_include_SubscriptionManager_H_
diff --git a/automotive/vehicle/aidl/impl/vhal/src/SubscriptionManager.cpp b/automotive/vehicle/aidl/impl/vhal/src/SubscriptionManager.cpp
new file mode 100644
index 0000000..dc9a6ce
--- /dev/null
+++ b/automotive/vehicle/aidl/impl/vhal/src/SubscriptionManager.cpp
@@ -0,0 +1,240 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "SubscriptionManager.h"
+
+#include <math/HashCombine.h>
+#include <utils/Log.h>
+
+namespace android {
+namespace hardware {
+namespace automotive {
+namespace vehicle {
+
+namespace {
+
+constexpr float ONE_SECOND_IN_NANO = 1000000000.;
+
+}  // namespace
+
+using ::aidl::android::hardware::automotive::vehicle::IVehicleCallback;
+using ::aidl::android::hardware::automotive::vehicle::SubscribeOptions;
+using ::aidl::android::hardware::automotive::vehicle::VehiclePropValue;
+using ::android::base::Error;
+using ::android::base::Result;
+using ::ndk::ScopedAStatus;
+
+bool SubscriptionManager::PropIdAreaId::operator==(const PropIdAreaId& other) const {
+    return areaId == other.areaId && propId == other.propId;
+}
+
+size_t SubscriptionManager::PropIdAreaIdHash::operator()(PropIdAreaId const& propIdAreaId) const {
+    size_t res = 0;
+    hashCombine(res, propIdAreaId.propId);
+    hashCombine(res, propIdAreaId.areaId);
+    return res;
+}
+
+SubscriptionManager::SubscriptionManager(GetValueFunc&& action)
+    : mTimer(std::make_shared<RecurrentTimer>()), mGetValue(std::move(action)) {}
+
+SubscriptionManager::~SubscriptionManager() {
+    std::scoped_lock<std::mutex> lockGuard(mLock);
+
+    mClientsByPropIdArea.clear();
+    mSubscriptionsByClient.clear();
+}
+
+bool SubscriptionManager::checkSampleRate(float sampleRate) {
+    return getInterval(sampleRate).ok();
+}
+
+Result<int64_t> SubscriptionManager::getInterval(float sampleRate) {
+    int64_t interval = 0;
+    if (sampleRate <= 0) {
+        return Error() << "invalid sample rate, must be a positive number";
+    }
+    if (sampleRate <= (ONE_SECOND_IN_NANO / static_cast<float>(INT64_MAX))) {
+        return Error() << "invalid sample rate: " << sampleRate << ", too small";
+    }
+    interval = static_cast<int64_t>(ONE_SECOND_IN_NANO / sampleRate);
+    return interval;
+}
+
+Result<void> SubscriptionManager::subscribe(const std::shared_ptr<IVehicleCallback>& callback,
+                                            const std::vector<SubscribeOptions>& options,
+                                            bool isContinuousProperty) {
+    std::scoped_lock<std::mutex> lockGuard(mLock);
+
+    std::vector<int64_t> intervals;
+
+    for (const auto& option : options) {
+        float sampleRate = option.sampleRate;
+
+        if (isContinuousProperty) {
+            auto intervalResult = getInterval(sampleRate);
+            if (!intervalResult.ok()) {
+                return intervalResult.error();
+            }
+            intervals.push_back(intervalResult.value());
+        }
+
+        if (option.areaIds.empty()) {
+            ALOGE("area IDs to subscribe must not be empty");
+            return Error() << "area IDs to subscribe must not be empty";
+        }
+    }
+
+    size_t intervalIndex = 0;
+    for (const auto& option : options) {
+        int32_t propId = option.propId;
+        const std::vector<int32_t>& areaIds = option.areaIds;
+        int64_t interval = 0;
+        if (isContinuousProperty) {
+            interval = intervals[intervalIndex];
+            intervalIndex++;
+        }
+        for (int32_t areaId : areaIds) {
+            PropIdAreaId propIdAreaId = {
+                    .propId = propId,
+                    .areaId = areaId,
+            };
+            if (isContinuousProperty) {
+                VehiclePropValue propValueRequest{
+                        .prop = propId,
+                        .areaId = areaId,
+                };
+                mSubscriptionsByClient[callback][propIdAreaId] =
+                        std::make_unique<RecurrentSubscription>(
+                                mTimer,
+                                [this, callback, propValueRequest] {
+                                    mGetValue(callback, propValueRequest);
+                                },
+                                interval);
+            } else {
+                mSubscriptionsByClient[callback][propIdAreaId] =
+                        std::make_unique<OnChangeSubscription>();
+            }
+            mClientsByPropIdArea[propIdAreaId].insert(callback);
+        }
+    }
+    return {};
+}
+
+Result<void> SubscriptionManager::unsubscribe(const std::shared_ptr<IVehicleCallback>& callback,
+                                              const std::vector<int32_t>& propIds) {
+    std::scoped_lock<std::mutex> lockGuard(mLock);
+
+    if (mSubscriptionsByClient.find(callback) == mSubscriptionsByClient.end()) {
+        return Error() << "No property was subscribed for the callback";
+    }
+    std::unordered_set<int32_t> subscribedPropIds;
+    for (auto const& [propIdAreaId, _] : mSubscriptionsByClient[callback]) {
+        subscribedPropIds.insert(propIdAreaId.propId);
+    }
+
+    for (int32_t propId : propIds) {
+        if (subscribedPropIds.find(propId) == subscribedPropIds.end()) {
+            return Error() << "property ID: " << propId << " is not subscribed";
+        }
+    }
+
+    auto& subscriptions = mSubscriptionsByClient[callback];
+    auto it = subscriptions.begin();
+    while (it != subscriptions.end()) {
+        int32_t propId = it->first.propId;
+        if (std::find(propIds.begin(), propIds.end(), propId) != propIds.end()) {
+            auto& clients = mClientsByPropIdArea[it->first];
+            clients.erase(callback);
+            if (clients.empty()) {
+                mClientsByPropIdArea.erase(it->first);
+            }
+            it = subscriptions.erase(it);
+        } else {
+            it++;
+        }
+    }
+    if (subscriptions.empty()) {
+        mSubscriptionsByClient.erase(callback);
+    }
+    return {};
+}
+
+Result<void> SubscriptionManager::unsubscribe(const std::shared_ptr<IVehicleCallback>& callback) {
+    std::scoped_lock<std::mutex> lockGuard(mLock);
+
+    if (mSubscriptionsByClient.find(callback) == mSubscriptionsByClient.end()) {
+        return Error() << "No property was subscribed for the callback";
+    }
+
+    auto& subscriptions = mSubscriptionsByClient[callback];
+    for (auto const& [propIdAreaId, _] : subscriptions) {
+        auto& clients = mClientsByPropIdArea[propIdAreaId];
+        clients.erase(callback);
+        if (clients.empty()) {
+            mClientsByPropIdArea.erase(propIdAreaId);
+        }
+    }
+    mSubscriptionsByClient.erase(callback);
+    return {};
+}
+
+std::unordered_map<std::shared_ptr<IVehicleCallback>, std::vector<const VehiclePropValue*>>
+SubscriptionManager::getSubscribedClients(const std::vector<VehiclePropValue>& updatedValues) {
+    std::scoped_lock<std::mutex> lockGuard(mLock);
+    std::unordered_map<std::shared_ptr<IVehicleCallback>, std::vector<const VehiclePropValue*>>
+            clients;
+
+    for (const auto& value : updatedValues) {
+        PropIdAreaId propIdAreaId{
+                .propId = value.prop,
+                .areaId = value.areaId,
+        };
+        if (mClientsByPropIdArea.find(propIdAreaId) == mClientsByPropIdArea.end()) {
+            continue;
+        }
+        for (const auto& client : mClientsByPropIdArea[propIdAreaId]) {
+            if (!mSubscriptionsByClient[client][propIdAreaId]->isOnChange()) {
+                continue;
+            }
+            clients[client].push_back(&value);
+        }
+    }
+    return clients;
+}
+
+SubscriptionManager::RecurrentSubscription::RecurrentSubscription(
+        std::shared_ptr<RecurrentTimer> timer, std::function<void()>&& action, int64_t interval)
+    : mAction(std::make_shared<std::function<void()>>(action)), mTimer(timer) {
+    mTimer->registerTimerCallback(interval, mAction);
+}
+
+SubscriptionManager::RecurrentSubscription::~RecurrentSubscription() {
+    mTimer->unregisterTimerCallback(mAction);
+}
+
+bool SubscriptionManager::RecurrentSubscription::isOnChange() {
+    return false;
+}
+
+bool SubscriptionManager::OnChangeSubscription::isOnChange() {
+    return true;
+}
+
+}  // namespace vehicle
+}  // namespace automotive
+}  // namespace hardware
+}  // namespace android
diff --git a/automotive/vehicle/aidl/impl/vhal/test/SubscriptionManagerTest.cpp b/automotive/vehicle/aidl/impl/vhal/test/SubscriptionManagerTest.cpp
new file mode 100644
index 0000000..fa08d6c
--- /dev/null
+++ b/automotive/vehicle/aidl/impl/vhal/test/SubscriptionManagerTest.cpp
@@ -0,0 +1,483 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "SubscriptionManager.h"
+
+#include <VehicleHalTypes.h>
+
+#include <aidl/android/hardware/automotive/vehicle/BnVehicleCallback.h>
+#include <android-base/thread_annotations.h>
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+
+#include <float.h>
+#include <chrono>
+#include <list>
+#include <memory>
+#include <mutex>
+#include <thread>
+#include <vector>
+
+namespace android {
+namespace hardware {
+namespace automotive {
+namespace vehicle {
+
+using ::aidl::android::hardware::automotive::vehicle::BnVehicleCallback;
+using ::aidl::android::hardware::automotive::vehicle::GetValueResults;
+using ::aidl::android::hardware::automotive::vehicle::IVehicleCallback;
+using ::aidl::android::hardware::automotive::vehicle::SetValueResults;
+using ::aidl::android::hardware::automotive::vehicle::SubscribeOptions;
+using ::aidl::android::hardware::automotive::vehicle::VehiclePropErrors;
+using ::aidl::android::hardware::automotive::vehicle::VehiclePropValue;
+using ::aidl::android::hardware::automotive::vehicle::VehiclePropValues;
+using ::ndk::ScopedAStatus;
+using ::testing::ElementsAre;
+using ::testing::WhenSorted;
+
+class PropertyCallback final : public BnVehicleCallback {
+  public:
+    ScopedAStatus onGetValues(const GetValueResults&) override { return ScopedAStatus::ok(); }
+
+    ScopedAStatus onSetValues(const SetValueResults&) override { return ScopedAStatus::ok(); }
+
+    ScopedAStatus onPropertyEvent(const VehiclePropValues& values, int32_t) override {
+        std::scoped_lock<std::mutex> lockGuard(mLock);
+        for (const auto& value : values.payloads) {
+            mEvents.push_back(value);
+        }
+        return ScopedAStatus::ok();
+    }
+
+    ScopedAStatus onPropertySetError(const VehiclePropErrors&) override {
+        return ScopedAStatus::ok();
+    }
+
+    // Test functions.
+    std::list<VehiclePropValue> getEvents() {
+        std::scoped_lock<std::mutex> lockGuard(mLock);
+        return mEvents;
+    }
+
+    void clearEvents() {
+        std::scoped_lock<std::mutex> lockGuard(mLock);
+        mEvents.clear();
+    }
+
+  private:
+    std::mutex mLock;
+    std::list<VehiclePropValue> mEvents GUARDED_BY(mLock);
+};
+
+class SubscriptionManagerTest : public ::testing::Test {
+  public:
+    void SetUp() override {
+        mManager = std::make_unique<SubscriptionManager>(
+                [](const std::shared_ptr<IVehicleCallback>& callback,
+                   const VehiclePropValue& value) {
+                    callback->onPropertyEvent(
+                            VehiclePropValues{
+                                    .payloads = {value},
+                            },
+                            0);
+                });
+        mCallback = ::ndk::SharedRefBase::make<PropertyCallback>();
+        mCallbackClient = IVehicleCallback::fromBinder(mCallback->asBinder());
+    }
+
+    SubscriptionManager* getManager() { return mManager.get(); }
+
+    std::shared_ptr<IVehicleCallback> getCallbackClient() { return mCallbackClient; }
+
+    PropertyCallback* getCallback() { return mCallback.get(); }
+
+    std::list<VehiclePropValue> getEvents() { return getCallback()->getEvents(); }
+
+    void clearEvents() { return getCallback()->clearEvents(); }
+
+  private:
+    std::unique_ptr<SubscriptionManager> mManager;
+    std::shared_ptr<PropertyCallback> mCallback;
+    std::shared_ptr<IVehicleCallback> mCallbackClient;
+};
+
+TEST_F(SubscriptionManagerTest, testSubscribeGlobalContinuous) {
+    std::vector<SubscribeOptions> options = {{
+            .propId = 0,
+            .areaIds = {0},
+            .sampleRate = 10.0,
+    }};
+
+    auto result = getManager()->subscribe(getCallbackClient(), options, true);
+    ASSERT_TRUE(result.ok()) << "failed to subscribe: " << result.error().message();
+
+    std::this_thread::sleep_for(std::chrono::seconds(1));
+
+    // Theoretically trigger 10 times, but check for at least 9 times to be stable.
+    ASSERT_GE(getEvents().size(), static_cast<size_t>(9));
+    EXPECT_EQ(getEvents().back().prop, 0);
+    EXPECT_EQ(getEvents().back().areaId, 0);
+}
+
+TEST_F(SubscriptionManagerTest, testSubscribeMultiplePropsGlobalContinuous) {
+    std::vector<SubscribeOptions> options = {{
+                                                     .propId = 0,
+                                                     .areaIds = {0},
+                                                     .sampleRate = 10.0,
+                                             },
+                                             {
+                                                     .propId = 1,
+                                                     .areaIds = {0},
+                                                     .sampleRate = 20.0,
+                                             }};
+
+    auto result = getManager()->subscribe(getCallbackClient(), options, true);
+    ASSERT_TRUE(result.ok()) << "failed to subscribe: " << result.error().message();
+
+    std::this_thread::sleep_for(std::chrono::seconds(1));
+
+    size_t event0Count = 0;
+    size_t event1Count = 0;
+
+    for (const auto& event : getEvents()) {
+        if (event.prop == 0) {
+            event0Count++;
+        } else {
+            event1Count++;
+        }
+    }
+
+    // Theoretically trigger 10 times, but check for at least 9 times to be stable.
+    EXPECT_GE(event0Count, static_cast<size_t>(9));
+    // Theoretically trigger 20 times, but check for at least 15 times to be stable.
+    EXPECT_GE(event1Count, static_cast<size_t>(15));
+}
+
+TEST_F(SubscriptionManagerTest, testOverrideSubscriptionContinuous) {
+    std::vector<SubscribeOptions> options = {{
+            .propId = 0,
+            .areaIds = {0},
+            .sampleRate = 20.0,
+    }};
+
+    auto result = getManager()->subscribe(getCallbackClient(), options, true);
+    ASSERT_TRUE(result.ok()) << "failed to subscribe: " << result.error().message();
+
+    // Override sample rate to be 10.0.
+    options[0].sampleRate = 10.0;
+    result = getManager()->subscribe(getCallbackClient(), options, true);
+    ASSERT_TRUE(result.ok()) << "failed to subscribe: " << result.error().message();
+
+    std::this_thread::sleep_for(std::chrono::seconds(1));
+
+    // Theoretically trigger 10 times, but check for at least 9 times to be stable.
+    EXPECT_GE(getEvents().size(), static_cast<size_t>(9));
+    EXPECT_LE(getEvents().size(), static_cast<size_t>(11));
+}
+
+TEST_F(SubscriptionManagerTest, testSubscribeMultipleAreasContinuous) {
+    std::vector<SubscribeOptions> options = {
+            {
+                    .propId = 0,
+                    .areaIds = {0, 1},
+                    .sampleRate = 10.0,
+            },
+    };
+
+    auto result = getManager()->subscribe(getCallbackClient(), options, true);
+    ASSERT_TRUE(result.ok()) << "failed to subscribe: " << result.error().message();
+
+    std::this_thread::sleep_for(std::chrono::seconds(1));
+
+    size_t area0Count = 0;
+    size_t area1Count = 0;
+
+    for (const auto& event : getEvents()) {
+        if (event.areaId == 0) {
+            area0Count++;
+        } else {
+            area1Count++;
+        }
+    }
+
+    // Theoretically trigger 10 times, but check for at least 9 times to be stable.
+    EXPECT_GE(area0Count, static_cast<size_t>(9));
+    // Theoretically trigger 10 times, but check for at least 9 times to be stable.
+    EXPECT_GE(area1Count, static_cast<size_t>(9));
+}
+
+TEST_F(SubscriptionManagerTest, testUnsubscribeGlobalContinuous) {
+    std::vector<SubscribeOptions> options = {{
+            .propId = 0,
+            .areaIds = {0},
+            .sampleRate = 10.0,
+    }};
+
+    auto result = getManager()->subscribe(getCallbackClient(), options, true);
+    ASSERT_TRUE(result.ok()) << "failed to subscribe: " << result.error().message();
+
+    result = getManager()->unsubscribe(getCallbackClient());
+    ASSERT_TRUE(result.ok()) << "failed to unsubscribe: " << result.error().message();
+
+    clearEvents();
+
+    std::this_thread::sleep_for(std::chrono::milliseconds(200));
+
+    // Theoretically trigger 10 times, but check for at least 9 times to be stable.
+    ASSERT_TRUE(getEvents().empty());
+}
+
+TEST_F(SubscriptionManagerTest, testUnsubscribeMultipleAreas) {
+    std::vector<SubscribeOptions> options = {
+            {
+                    .propId = 0,
+                    .areaIds = {0, 1, 2, 3, 4},
+                    .sampleRate = 10.0,
+            },
+            {
+                    .propId = 1,
+                    .areaIds = {0},
+                    .sampleRate = 10.0,
+            },
+    };
+
+    auto result = getManager()->subscribe(getCallbackClient(), options, true);
+    ASSERT_TRUE(result.ok()) << "failed to subscribe: " << result.error().message();
+
+    result = getManager()->unsubscribe(getCallbackClient(), std::vector<int32_t>({0}));
+    ASSERT_TRUE(result.ok()) << "failed to unsubscribe: " << result.error().message();
+
+    clearEvents();
+
+    std::this_thread::sleep_for(std::chrono::seconds(1));
+
+    // Theoretically trigger 10 times, but check for at least 9 times to be stable.
+    EXPECT_GE(getEvents().size(), static_cast<size_t>(9));
+
+    for (const auto& event : getEvents()) {
+        EXPECT_EQ(event.prop, 1);
+    }
+}
+
+TEST_F(SubscriptionManagerTest, testUnsubscribeByCallback) {
+    std::vector<SubscribeOptions> options = {
+            {
+                    .propId = 0,
+                    .areaIds = {0, 1, 2, 3, 4},
+                    .sampleRate = 10.0,
+            },
+            {
+                    .propId = 1,
+                    .areaIds = {0},
+                    .sampleRate = 10.0,
+            },
+    };
+
+    auto result = getManager()->subscribe(getCallbackClient(), options, true);
+    ASSERT_TRUE(result.ok()) << "failed to subscribe: " << result.error().message();
+
+    result = getManager()->unsubscribe(getCallbackClient());
+    ASSERT_TRUE(result.ok()) << "failed to unsubscribe: " << result.error().message();
+
+    clearEvents();
+
+    std::this_thread::sleep_for(std::chrono::seconds(1));
+
+    EXPECT_TRUE(getEvents().empty());
+}
+
+TEST_F(SubscriptionManagerTest, testUnsubscribeFailure) {
+    std::vector<SubscribeOptions> options = {
+            {
+                    .propId = 0,
+                    .areaIds = {0, 1, 2, 3, 4},
+            },
+            {
+                    .propId = 1,
+                    .areaIds = {0},
+            },
+    };
+
+    auto result = getManager()->subscribe(getCallbackClient(), options, false);
+    ASSERT_TRUE(result.ok()) << "failed to subscribe: " << result.error().message();
+
+    // Property ID: 2 was not subscribed.
+    result = getManager()->unsubscribe(getCallbackClient(), std::vector<int32_t>({0, 1, 2}));
+    ASSERT_FALSE(result.ok()) << "unsubscribe an unsubscribed property must fail";
+
+    // Since property 0 and property 1 was not unsubscribed successfully, we should be able to
+    // unsubscribe them again.
+    result = getManager()->unsubscribe(getCallbackClient(), std::vector<int32_t>({0, 1}));
+    ASSERT_TRUE(result.ok()) << "a failed unsubscription must not unsubscribe any properties"
+                             << result.error().message();
+}
+
+TEST_F(SubscriptionManagerTest, testSubscribeOnchange) {
+    std::vector<SubscribeOptions> options1 = {
+            {
+                    .propId = 0,
+                    .areaIds = {0, 1},
+            },
+            {
+                    .propId = 1,
+                    .areaIds = {0},
+            },
+    };
+    std::vector<SubscribeOptions> options2 = {
+            {
+                    .propId = 0,
+                    .areaIds = {0},
+            },
+    };
+
+    std::shared_ptr<IVehicleCallback> client1 = IVehicleCallback::fromBinder(
+            ::ndk::SharedRefBase::make<PropertyCallback>()->asBinder());
+    std::shared_ptr<IVehicleCallback> client2 = IVehicleCallback::fromBinder(
+            ::ndk::SharedRefBase::make<PropertyCallback>()->asBinder());
+    auto result = getManager()->subscribe(client1, options1, false);
+    ASSERT_TRUE(result.ok()) << "failed to subscribe: " << result.error().message();
+    result = getManager()->subscribe(client2, options2, false);
+    ASSERT_TRUE(result.ok()) << "failed to subscribe: " << result.error().message();
+
+    std::vector<VehiclePropValue> updatedValues = {
+            {
+                    .prop = 0,
+                    .areaId = 0,
+            },
+            {
+                    .prop = 0,
+                    .areaId = 1,
+            },
+            {
+                    .prop = 1,
+                    .areaId = 0,
+            },
+            {
+                    .prop = 1,
+                    .areaId = 1,
+            },
+    };
+    auto clients = getManager()->getSubscribedClients(updatedValues);
+
+    ASSERT_THAT(clients[client1],
+                WhenSorted(ElementsAre(&updatedValues[0], &updatedValues[1], &updatedValues[2])));
+    ASSERT_THAT(clients[client2], ElementsAre(&updatedValues[0]));
+}
+
+TEST_F(SubscriptionManagerTest, testSubscribeInvalidOption) {
+    std::vector<SubscribeOptions> options = {
+            {
+                    .propId = 0,
+                    .areaIds = {0, 1, 2, 3, 4},
+                    // invalid sample rate.
+                    .sampleRate = 0.0,
+            },
+            {
+                    .propId = 1,
+                    .areaIds = {0},
+                    .sampleRate = 10.0,
+            },
+    };
+
+    auto result = getManager()->subscribe(getCallbackClient(), options, true);
+    ASSERT_FALSE(result.ok()) << "subscribe with invalid sample rate must fail";
+    ASSERT_TRUE(getManager()
+                        ->getSubscribedClients({{
+                                                        .prop = 0,
+                                                        .areaId = 0,
+                                                },
+                                                {
+                                                        .prop = 1,
+                                                        .areaId = 0,
+                                                }})
+                        .empty())
+            << "no property should be subscribed if error is returned";
+}
+
+TEST_F(SubscriptionManagerTest, testSubscribeNoAreaIds) {
+    std::vector<SubscribeOptions> options = {
+            {
+                    .propId = 0,
+                    .areaIds = {},
+                    .sampleRate = 1.0,
+            },
+            {
+                    .propId = 1,
+                    .areaIds = {0},
+                    .sampleRate = 10.0,
+            },
+    };
+
+    auto result = getManager()->subscribe(getCallbackClient(), options, true);
+    ASSERT_FALSE(result.ok()) << "subscribe with invalid sample rate must fail";
+    ASSERT_TRUE(getManager()
+                        ->getSubscribedClients({{
+                                .prop = 1,
+                                .areaId = 0,
+                        }})
+                        .empty())
+            << "no property should be subscribed if error is returned";
+}
+
+TEST_F(SubscriptionManagerTest, testUnsubscribeOnchange) {
+    std::vector<SubscribeOptions> options = {
+            {
+                    .propId = 0,
+                    .areaIds = {0, 1},
+            },
+            {
+                    .propId = 1,
+                    .areaIds = {0},
+            },
+    };
+
+    auto result = getManager()->subscribe(getCallbackClient(), options, false);
+    ASSERT_TRUE(result.ok()) << "failed to subscribe: " << result.error().message();
+
+    result = getManager()->unsubscribe(getCallbackClient(), std::vector<int32_t>({0}));
+    ASSERT_TRUE(result.ok()) << "failed to unsubscribe: " << result.error().message();
+
+    std::vector<VehiclePropValue> updatedValues = {
+            {
+                    .prop = 0,
+                    .areaId = 0,
+            },
+            {
+                    .prop = 1,
+                    .areaId = 0,
+            },
+    };
+    auto clients = getManager()->getSubscribedClients(updatedValues);
+
+    ASSERT_THAT(clients[getCallbackClient()], ElementsAre(&updatedValues[1]));
+}
+
+TEST_F(SubscriptionManagerTest, testCheckSampleRateValid) {
+    ASSERT_TRUE(SubscriptionManager::checkSampleRate(1.0));
+}
+
+TEST_F(SubscriptionManagerTest, testCheckSampleRateInvalidTooSmall) {
+    ASSERT_FALSE(SubscriptionManager::checkSampleRate(FLT_MIN));
+}
+
+TEST_F(SubscriptionManagerTest, testCheckSampleRateInvalidZero) {
+    ASSERT_FALSE(SubscriptionManager::checkSampleRate(0));
+}
+
+}  // namespace vehicle
+}  // namespace automotive
+}  // namespace hardware
+}  // namespace android