diff --git a/ui/build/bazel_metrics.go b/ui/build/bazel_metrics.go
index c0690c1..3f9fbb1 100644
--- a/ui/build/bazel_metrics.go
+++ b/ui/build/bazel_metrics.go
@@ -121,6 +121,7 @@
 			}
 		}
 		bazelMetrics.PhaseTimings = phaseTimings
+		bazelMetrics.BesId = proto.String(config.besId)
 
 		return bazelMetrics
 	}
diff --git a/ui/build/config.go b/ui/build/config.go
index d825754..80038f5 100644
--- a/ui/build/config.go
+++ b/ui/build/config.go
@@ -90,8 +90,9 @@
 	skipMetricsUpload        bool
 	buildStartedTime         int64 // For metrics-upload-only - manually specify a build-started time
 	buildFromTextStub        bool
-	ensureAllowlistIntegrity bool  // For CI builds - make sure modules are mixed-built
-	bazelExitCode            int32 // For b-runs - necessary for updating NonZeroExit
+	ensureAllowlistIntegrity bool   // For CI builds - make sure modules are mixed-built
+	bazelExitCode            int32  // For b runs - necessary for updating NonZeroExit
+	besId                    string // For b runs, to identify the BuildEventService logs
 
 	// From the product config
 	katiArgs        []string
@@ -908,6 +909,8 @@
 			} else {
 				ctx.Fatalf("Error parsing bazel-exit-code", err)
 			}
+		} else if strings.HasPrefix(arg, "--bes-id=") {
+			c.besId = strings.TrimPrefix(arg, "--bes-id=")
 		} else if len(arg) > 0 && arg[0] == '-' {
 			parseArgNum := func(def int) int {
 				if len(arg) > 2 {