diff --git a/java/com/android/dialer/telecom/TelecomUtil.java b/java/com/android/dialer/telecom/TelecomUtil.java
index 8ff4b39..3bf9b46 100644
--- a/java/com/android/dialer/telecom/TelecomUtil.java
+++ b/java/com/android/dialer/telecom/TelecomUtil.java
@@ -17,6 +17,7 @@
 package com.android.dialer.telecom;
 
 import android.Manifest;
+import android.Manifest.permission;
 import android.content.Context;
 import android.content.Intent;
 import android.content.pm.PackageManager;
@@ -24,7 +25,9 @@
 import android.os.Build.VERSION;
 import android.os.Build.VERSION_CODES;
 import android.provider.CallLog.Calls;
+import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
+import android.support.annotation.RequiresPermission;
 import android.support.annotation.VisibleForTesting;
 import android.support.v4.content.ContextCompat;
 import android.telecom.PhoneAccount;
@@ -234,6 +237,26 @@
     return instance.isDefaultDialer(context);
   }
 
+  /** @return the other SIM based PhoneAccountHandle that is not {@code currentAccount} */
+  @Nullable
+  @RequiresPermission(permission.READ_PHONE_STATE)
+  @SuppressWarnings("MissingPermission")
+  public static PhoneAccountHandle getOtherAccount(
+      @NonNull Context context, @Nullable PhoneAccountHandle currentAccount) {
+    if (currentAccount == null) {
+      return null;
+    }
+    TelecomManager telecomManager = context.getSystemService(TelecomManager.class);
+    for (PhoneAccountHandle phoneAccountHandle : telecomManager.getCallCapablePhoneAccounts()) {
+      PhoneAccount phoneAccount = telecomManager.getPhoneAccount(phoneAccountHandle);
+      if (phoneAccount.hasCapabilities(PhoneAccount.CAPABILITY_SIM_SUBSCRIPTION)
+          && !phoneAccountHandle.equals(currentAccount)) {
+        return phoneAccountHandle;
+      }
+    }
+    return null;
+  }
+
   /** Contains an implementation for {@link TelecomUtil} methods */
   @VisibleForTesting()
   public static class TelecomUtilImpl {
diff --git a/java/com/android/incallui/CallButtonPresenter.java b/java/com/android/incallui/CallButtonPresenter.java
index bd5bb78..b3fb97f 100644
--- a/java/com/android/incallui/CallButtonPresenter.java
+++ b/java/com/android/incallui/CallButtonPresenter.java
@@ -22,11 +22,14 @@
 import android.support.v4.app.Fragment;
 import android.support.v4.os.UserManagerCompat;
 import android.telecom.CallAudioState;
+import android.telecom.PhoneAccountHandle;
 import com.android.contacts.common.compat.CallCompat;
 import com.android.dialer.common.Assert;
 import com.android.dialer.common.LogUtil;
+import com.android.dialer.common.concurrent.DialerExecutorComponent;
 import com.android.dialer.logging.DialerImpression;
 import com.android.dialer.logging.Logger;
+import com.android.dialer.telecom.TelecomUtil;
 import com.android.incallui.InCallCameraManager.Listener;
 import com.android.incallui.InCallPresenter.CanAddCallListener;
 import com.android.incallui.InCallPresenter.InCallDetailsListener;
@@ -42,6 +45,7 @@
 import com.android.incallui.incall.protocol.InCallButtonIds;
 import com.android.incallui.incall.protocol.InCallButtonUi;
 import com.android.incallui.incall.protocol.InCallButtonUiDelegate;
+import com.android.incallui.multisim.SwapSimWorker;
 import com.android.incallui.videotech.utils.VideoUtils;
 
 /** Logic for call buttons. */
@@ -63,6 +67,7 @@
   private boolean mAutomaticallyMuted = false;
   private boolean mPreviousMuteState = false;
   private boolean isInCallButtonUiReady;
+  private PhoneAccountHandle mOtherAccount;
 
   public CallButtonPresenter(Context context) {
     mContext = context.getApplicationContext();
@@ -310,6 +315,23 @@
     mInCallButtonUi.showAudioRouteSelector();
   }
 
+  @Override
+  public void swapSimClicked() {
+    LogUtil.enterBlock("CallButtonPresenter.swapSimClicked");
+    SwapSimWorker worker =
+        new SwapSimWorker(
+            getContext(),
+            mCall,
+            InCallPresenter.getInstance().getCallList(),
+            mOtherAccount,
+            InCallPresenter.getInstance().acquireInCallUiLock("swapSim"));
+    DialerExecutorComponent.get(getContext())
+        .dialerExecutorFactory()
+        .createNonUiTaskBuilder(worker)
+        .build()
+        .executeParallel(null);
+  }
+
   /**
    * Switches the camera between the front-facing and back-facing camera.
    *
@@ -409,6 +431,7 @@
    *
    * @param call The active call.
    */
+  @SuppressWarnings("MissingPermission")
   private void updateButtonsState(DialerCall call) {
     LogUtil.v("CallButtonPresenter.updateButtonsState", "");
     final boolean isVideo = call.isVideoCall();
@@ -439,11 +462,15 @@
             && call.getState() != DialerCall.State.DIALING
             && call.getState() != DialerCall.State.CONNECTING;
 
+    mOtherAccount = TelecomUtil.getOtherAccount(getContext(), call.getAccountHandle());
+    boolean showSwapSim = mOtherAccount != null && DialerCall.State.isDialing(call.getState());
+
     mInCallButtonUi.showButton(InCallButtonIds.BUTTON_AUDIO, true);
     mInCallButtonUi.showButton(InCallButtonIds.BUTTON_SWAP, showSwap);
     mInCallButtonUi.showButton(InCallButtonIds.BUTTON_HOLD, showHold);
     mInCallButtonUi.setHold(isCallOnHold);
     mInCallButtonUi.showButton(InCallButtonIds.BUTTON_MUTE, showMute);
+    mInCallButtonUi.showButton(InCallButtonIds.BUTTON_SWAP_SIM, showSwapSim);
     mInCallButtonUi.showButton(InCallButtonIds.BUTTON_ADD_CALL, true);
     mInCallButtonUi.enableButton(InCallButtonIds.BUTTON_ADD_CALL, showAddCall);
     mInCallButtonUi.showButton(InCallButtonIds.BUTTON_UPGRADE_TO_VIDEO, showUpgradeToVideo);
@@ -532,4 +559,5 @@
     }
     return null;
   }
+
 }
diff --git a/java/com/android/incallui/callpending/CallPendingActivity.java b/java/com/android/incallui/callpending/CallPendingActivity.java
index 7fc4caf..47325d8 100644
--- a/java/com/android/incallui/callpending/CallPendingActivity.java
+++ b/java/com/android/incallui/callpending/CallPendingActivity.java
@@ -279,6 +279,9 @@
           public void showAudioRouteSelector() {}
 
           @Override
+          public void swapSimClicked() {}
+
+          @Override
           public Context getContext() {
             return CallPendingActivity.this;
           }
diff --git a/java/com/android/incallui/commontheme/res/values/strings.xml b/java/com/android/incallui/commontheme/res/values/strings.xml
index 94a8c90..f366a86 100644
--- a/java/com/android/incallui/commontheme/res/values/strings.xml
+++ b/java/com/android/incallui/commontheme/res/values/strings.xml
@@ -24,6 +24,8 @@
 
   <string name="incall_content_description_swap_calls">Swap calls</string>
 
+  <string name="incall_content_description_swap_sim">Change SIM</string>
+
   <string name="incall_content_description_merge_calls">Merge calls</string>
 
   <string name="incall_content_description_earpiece">Handset earpiece</string>
diff --git a/java/com/android/incallui/incall/impl/ButtonChooserFactory.java b/java/com/android/incallui/incall/impl/ButtonChooserFactory.java
index 0f4a95d..0d0a932 100644
--- a/java/com/android/incallui/incall/impl/ButtonChooserFactory.java
+++ b/java/com/android/incallui/incall/impl/ButtonChooserFactory.java
@@ -112,6 +112,7 @@
     mapping.put(InCallButtonIds.BUTTON_AUDIO, MappingInfo.builder(2).build());
     mapping.put(InCallButtonIds.BUTTON_MERGE, MappingInfo.builder(3).setSlotOrder(0).build());
     mapping.put(InCallButtonIds.BUTTON_ADD_CALL, MappingInfo.builder(3).build());
+    mapping.put(InCallButtonIds.BUTTON_SWAP_SIM, MappingInfo.builder(4).build());
     return mapping;
   }
 }
diff --git a/java/com/android/incallui/incall/impl/ButtonController.java b/java/com/android/incallui/incall/impl/ButtonController.java
index b7a47f0..cefbd72 100644
--- a/java/com/android/incallui/incall/impl/ButtonController.java
+++ b/java/com/android/incallui/incall/impl/ButtonController.java
@@ -560,4 +560,21 @@
       inCallScreenDelegate.onSecondaryInfoClicked();
     }
   }
+
+  class SwapSimButtonController extends SimpleNonCheckableButtonController {
+
+    public SwapSimButtonController(InCallButtonUiDelegate delegate) {
+      super(
+          delegate,
+          InCallButtonIds.BUTTON_SWAP_SIM,
+          R.string.incall_content_description_swap_sim,
+          R.string.incall_label_swap_sim,
+          R.drawable.quantum_ic_swap_calls_white_36);
+    }
+
+    @Override
+    public void onClick(View view) {
+      delegate.swapSimClicked();
+    }
+  }
 }
diff --git a/java/com/android/incallui/incall/impl/InCallFragment.java b/java/com/android/incallui/incall/impl/InCallFragment.java
index 1317565..f0504bc 100644
--- a/java/com/android/incallui/incall/impl/InCallFragment.java
+++ b/java/com/android/incallui/incall/impl/InCallFragment.java
@@ -110,7 +110,8 @@
         || id == InCallButtonIds.BUTTON_UPGRADE_TO_VIDEO
         || id == InCallButtonIds.BUTTON_ADD_CALL
         || id == InCallButtonIds.BUTTON_MERGE
-        || id == InCallButtonIds.BUTTON_MANAGE_VOICE_CONFERENCE;
+        || id == InCallButtonIds.BUTTON_MANAGE_VOICE_CONFERENCE
+        || id == InCallButtonIds.BUTTON_SWAP_SIM;
   }
 
   @Override
@@ -198,6 +199,7 @@
     buttonControllers.add(new ButtonController.AddCallButtonController(inCallButtonUiDelegate));
     buttonControllers.add(new ButtonController.SwapButtonController(inCallButtonUiDelegate));
     buttonControllers.add(new ButtonController.MergeButtonController(inCallButtonUiDelegate));
+    buttonControllers.add(new ButtonController.SwapSimButtonController(inCallButtonUiDelegate));
     buttonControllers.add(
         new ButtonController.UpgradeToVideoButtonController(inCallButtonUiDelegate));
     buttonControllers.add(
diff --git a/java/com/android/incallui/incall/impl/res/values/strings.xml b/java/com/android/incallui/incall/impl/res/values/strings.xml
index 2b30dfa..d021756 100644
--- a/java/com/android/incallui/incall/impl/res/values/strings.xml
+++ b/java/com/android/incallui/incall/impl/res/values/strings.xml
@@ -61,6 +61,10 @@
   <string name="incall_label_swap">Swap</string>
 
 
+  <!-- Button shown during a call with a multi-SIM device to hang up and call with the other SIM
+     instead. [CHAR LIMIT=12] -->
+  <string name="incall_label_swap_sim">Change SIM</string>
+
   <!-- Used to inform the user that the note associated with an outgoing call has been sent.
        [CHAR LIMIT=32] -->
   <string name="incall_note_sent">Note sent</string>
diff --git a/java/com/android/incallui/incall/protocol/InCallButtonIds.java b/java/com/android/incallui/incall/protocol/InCallButtonIds.java
index 50ebc64..3de5335 100644
--- a/java/com/android/incallui/incall/protocol/InCallButtonIds.java
+++ b/java/com/android/incallui/incall/protocol/InCallButtonIds.java
@@ -37,6 +37,7 @@
   InCallButtonIds.BUTTON_MANAGE_VIDEO_CONFERENCE,
   InCallButtonIds.BUTTON_MANAGE_VOICE_CONFERENCE,
   InCallButtonIds.BUTTON_SWITCH_TO_SECONDARY,
+  InCallButtonIds.BUTTON_SWAP_SIM,
   InCallButtonIds.BUTTON_COUNT,
 })
 public @interface InCallButtonIds {
@@ -55,5 +56,6 @@
   int BUTTON_MANAGE_VIDEO_CONFERENCE = 11;
   int BUTTON_MANAGE_VOICE_CONFERENCE = 12;
   int BUTTON_SWITCH_TO_SECONDARY = 13;
-  int BUTTON_COUNT = 14;
+  int BUTTON_SWAP_SIM = 14;
+  int BUTTON_COUNT = 15;
 }
diff --git a/java/com/android/incallui/incall/protocol/InCallButtonIdsExtension.java b/java/com/android/incallui/incall/protocol/InCallButtonIdsExtension.java
index 6d802e3..db6e900 100644
--- a/java/com/android/incallui/incall/protocol/InCallButtonIdsExtension.java
+++ b/java/com/android/incallui/incall/protocol/InCallButtonIdsExtension.java
@@ -54,6 +54,8 @@
       return "MANAGE_VOICE_CONFERENCE";
     } else if (id == InCallButtonIds.BUTTON_SWITCH_TO_SECONDARY) {
       return "SWITCH_TO_SECONDARY";
+    } else if (id == InCallButtonIds.BUTTON_SWAP_SIM) {
+      return "SWAP_SIM";
     } else {
       return "INVALID_BUTTON: " + id;
     }
diff --git a/java/com/android/incallui/incall/protocol/InCallButtonUiDelegate.java b/java/com/android/incallui/incall/protocol/InCallButtonUiDelegate.java
index e02ada9..9f9c5fb 100644
--- a/java/com/android/incallui/incall/protocol/InCallButtonUiDelegate.java
+++ b/java/com/android/incallui/incall/protocol/InCallButtonUiDelegate.java
@@ -63,5 +63,7 @@
 
   void showAudioRouteSelector();
 
+  void swapSimClicked();
+
   Context getContext();
 }
diff --git a/java/com/android/incallui/multisim/SwapSimWorker.java b/java/com/android/incallui/multisim/SwapSimWorker.java
new file mode 100644
index 0000000..73c18c4
--- /dev/null
+++ b/java/com/android/incallui/multisim/SwapSimWorker.java
@@ -0,0 +1,202 @@
+/*
+ * Copyright (C) 2017 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
+ */
+
+package com.android.incallui.multisim;
+
+import android.content.Context;
+import android.net.Uri;
+import android.os.Bundle;
+import android.support.annotation.MainThread;
+import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
+import android.support.annotation.VisibleForTesting;
+import android.support.annotation.WorkerThread;
+import android.telecom.PhoneAccount;
+import android.telecom.PhoneAccountHandle;
+import android.telecom.TelecomManager;
+import com.android.dialer.common.Assert;
+import com.android.dialer.common.LogUtil;
+import com.android.dialer.common.concurrent.DialerExecutor.Worker;
+import com.android.dialer.common.concurrent.ThreadUtil;
+import com.android.dialer.util.PermissionsUtil;
+import com.android.incallui.call.CallList;
+import com.android.incallui.call.DialerCall;
+import com.android.incallui.call.DialerCallListener;
+import com.android.incallui.incalluilock.InCallUiLock;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * Hangs up the current call and redial the call using the {@code otherAccount} instead. the in call
+ * ui will be prevented from closing until the process has finished.
+ */
+public class SwapSimWorker implements Worker<Void, Void>, DialerCallListener, CallList.Listener {
+
+  // Timeout waiting for the call to hangup or redial.
+  private static final int DEFAULT_TIMEOUT_MILLIS = 5_000;
+
+  private final Context context;
+  private final DialerCall call;
+  private final CallList callList;
+  private final InCallUiLock inCallUiLock;
+
+  private final CountDownLatch disconnectLatch = new CountDownLatch(1);
+  private final CountDownLatch dialingLatch = new CountDownLatch(1);
+
+  private final PhoneAccountHandle otherAccount;
+  private final String number;
+
+  private final int timeoutMillis;
+
+  private CountDownLatch latchForTest;
+
+  @MainThread
+  public SwapSimWorker(
+      Context context,
+      DialerCall call,
+      CallList callList,
+      PhoneAccountHandle otherAccount,
+      InCallUiLock lock) {
+    this(context, call, callList, otherAccount, lock, DEFAULT_TIMEOUT_MILLIS);
+  }
+
+  @VisibleForTesting
+  SwapSimWorker(
+      Context context,
+      DialerCall call,
+      CallList callList,
+      PhoneAccountHandle otherAccount,
+      InCallUiLock lock,
+      int timeoutMillis) {
+    Assert.isMainThread();
+    this.context = context;
+    this.call = call;
+    this.callList = callList;
+    this.otherAccount = otherAccount;
+    inCallUiLock = lock;
+    this.timeoutMillis = timeoutMillis;
+    number = call.getNumber();
+    call.addListener(this);
+    call.disconnect();
+  }
+
+  @WorkerThread
+  @Nullable
+  @Override
+  @SuppressWarnings("MissingPermission")
+  public Void doInBackground(Void unused) {
+    try {
+      if (!PermissionsUtil.hasPhonePermissions(context)) {
+        LogUtil.e("SwapSimWorker.doInBackground", "missing phone permission");
+        return null;
+      }
+      if (!disconnectLatch.await(timeoutMillis, TimeUnit.MILLISECONDS)) {
+        LogUtil.e("SwapSimWorker.doInBackground", "timeout waiting for call to disconnect");
+        return null;
+      }
+      LogUtil.i("SwapSimWorker.doInBackground", "call disconnected, redialing");
+      TelecomManager telecomManager = context.getSystemService(TelecomManager.class);
+      Bundle extras = new Bundle();
+      extras.putParcelable(TelecomManager.EXTRA_PHONE_ACCOUNT_HANDLE, otherAccount);
+      callList.addListener(this);
+      telecomManager.placeCall(Uri.fromParts(PhoneAccount.SCHEME_TEL, number, null), extras);
+      if (latchForTest != null) {
+        latchForTest.countDown();
+      }
+      if (!dialingLatch.await(timeoutMillis, TimeUnit.MILLISECONDS)) {
+        LogUtil.e("SwapSimWorker.doInBackground", "timeout waiting for call to dial");
+      }
+      return null;
+    } catch (InterruptedException e) {
+      LogUtil.e("SwapSimWorker.doInBackground", "interrupted", e);
+      Thread.currentThread().interrupt();
+      return null;
+    } finally {
+      ThreadUtil.postOnUiThread(
+          () -> {
+            call.removeListener(this);
+            callList.removeListener(this);
+            inCallUiLock.release();
+          });
+    }
+  }
+
+  @MainThread
+  @Override
+  public void onDialerCallDisconnect() {
+    disconnectLatch.countDown();
+  }
+
+  @Override
+  public void onCallListChange(CallList callList) {
+    if (callList.getOutgoingCall() != null) {
+      dialingLatch.countDown();
+    }
+  }
+
+  @VisibleForTesting
+  void setLatchForTest(CountDownLatch latch) {
+    latchForTest = latch;
+  }
+
+  @Override
+  public void onDialerCallUpdate() {}
+
+  @Override
+  public void onDialerCallChildNumberChange() {}
+
+  @Override
+  public void onDialerCallLastForwardedNumberChange() {}
+
+  @Override
+  public void onDialerCallUpgradeToVideo() {}
+
+  @Override
+  public void onDialerCallSessionModificationStateChange() {}
+
+  @Override
+  public void onWiFiToLteHandover() {}
+
+  @Override
+  public void onHandoverToWifiFailure() {}
+
+  @Override
+  public void onInternationalCallOnWifi() {}
+
+  @Override
+  public void onEnrichedCallSessionUpdate() {}
+
+  @Override
+  public void onIncomingCall(DialerCall call) {}
+
+  @Override
+  public void onUpgradeToVideo(DialerCall call) {}
+
+  @Override
+  public void onSessionModificationStateChange(DialerCall call) {}
+
+  @Override
+  public void onDisconnect(DialerCall call) {}
+
+  @Override
+  public void onWiFiToLteHandover(DialerCall call) {}
+
+  @Override
+  public void onHandoverToWifiFailed(DialerCall call) {}
+
+  @Override
+  public void onInternationalCallOnWifi(@NonNull DialerCall call) {}
+}