diff --git a/openapi/openapiv2.json b/openapi/openapiv2.json
index b99727843..b585fcbb7 100644
--- a/openapi/openapiv2.json
+++ b/openapi/openapiv2.json
@@ -13471,6 +13471,16 @@
         "startDelay": {
           "type": "string",
           "description": "Time to wait before dispatching the first activity task. This delay is not applied to retry attempts."
+        },
+        "requestedStartTime": {
+          "type": "string",
+          "format": "date-time",
+          "description": "The time at which the activity is requested to start, computed as `schedule_time + start_delay`.\nSame as `schedule_time` if `start_delay` is not set."
+        },
+        "actualStartTime": {
+          "type": "string",
+          "format": "date-time",
+          "description": "The time at which the activity was first dispatched to a worker (i.e. when a worker first picked\nup the task from matching). Not set until a worker picks up the first attempt. Not updated on\nsubsequent retry attempts."
         }
       },
       "description": "Information about a standalone activity."
@@ -13525,6 +13535,16 @@
         "executionDuration": {
           "type": "string",
           "description": "The difference between close time and scheduled time.\nThis field is only populated if the activity is closed."
+        },
+        "requestedStartTime": {
+          "type": "string",
+          "format": "date-time",
+          "description": "The time at which the activity is requested to start, computed as `schedule_time + start_delay`.\nSame as `schedule_time` if `start_delay` is not set."
+        },
+        "actualStartTime": {
+          "type": "string",
+          "format": "date-time",
+          "description": "The time at which the activity was first dispatched to a worker (i.e. when a worker first picked\nup the task from matching). Not set until a worker picks up the first attempt. Not updated on\nsubsequent retry attempts."
         }
       },
       "description": "Limited activity information returned in the list response.\nWhen adding fields here, ensure that it is also present in ActivityExecutionInfo (note that it\nmay already be present in ActivityExecutionInfo but not at the top-level)."
diff --git a/openapi/openapiv3.yaml b/openapi/openapiv3.yaml
index a0288e082..609fa9efa 100644
--- a/openapi/openapiv3.yaml
+++ b/openapi/openapiv3.yaml
@@ -9852,6 +9852,19 @@ components:
           pattern: ^-?(?:0|[1-9][0-9]{0,11})(?:\.[0-9]{1,9})?s$
           type: string
           description: Time to wait before dispatching the first activity task. This delay is not applied to retry attempts.
+        requestedStartTime:
+          type: string
+          description: |-
+            The time at which the activity is requested to start, computed as `schedule_time + start_delay`.
+             Same as `schedule_time` if `start_delay` is not set.
+          format: date-time
+        actualStartTime:
+          type: string
+          description: |-
+            The time at which the activity was first dispatched to a worker (i.e. when a worker first picked
+             up the task from matching). Not set until a worker picks up the first attempt. Not updated on
+             subsequent retry attempts.
+          format: date-time
       description: Information about a standalone activity.
     ActivityExecutionListInfo:
       type: object
@@ -9907,6 +9920,19 @@ components:
           description: |-
             The difference between close time and scheduled time.
              This field is only populated if the activity is closed.
+        requestedStartTime:
+          type: string
+          description: |-
+            The time at which the activity is requested to start, computed as `schedule_time + start_delay`.
+             Same as `schedule_time` if `start_delay` is not set.
+          format: date-time
+        actualStartTime:
+          type: string
+          description: |-
+            The time at which the activity was first dispatched to a worker (i.e. when a worker first picked
+             up the task from matching). Not set until a worker picks up the first attempt. Not updated on
+             subsequent retry attempts.
+          format: date-time
       description: |-
         Limited activity information returned in the list response.
          When adding fields here, ensure that it is also present in ActivityExecutionInfo (note that it
diff --git a/temporal/api/activity/v1/message.proto b/temporal/api/activity/v1/message.proto
index 6d77c7f12..765b8759e 100644
--- a/temporal/api/activity/v1/message.proto
+++ b/temporal/api/activity/v1/message.proto
@@ -186,6 +186,15 @@ message ActivityExecutionInfo {
 
     // Time to wait before dispatching the first activity task. This delay is not applied to retry attempts.
     google.protobuf.Duration start_delay = 37;
+
+    // The time at which the activity is requested to start, computed as `schedule_time + start_delay`.
+    // Same as `schedule_time` if `start_delay` is not set.
+    google.protobuf.Timestamp requested_start_time = 38;
+
+    // The time at which the activity was first dispatched to a worker (i.e. when a worker first picked
+    // up the task from matching). Not set until a worker picks up the first attempt. Not updated on
+    // subsequent retry attempts.
+    google.protobuf.Timestamp actual_start_time = 39;
 }
 
 // Limited activity information returned in the list response.
@@ -219,6 +228,15 @@ message ActivityExecutionListInfo {
     // The difference between close time and scheduled time.
     // This field is only populated if the activity is closed.
     google.protobuf.Duration execution_duration = 11;
+
+    // The time at which the activity is requested to start, computed as `schedule_time + start_delay`.
+    // Same as `schedule_time` if `start_delay` is not set.
+    google.protobuf.Timestamp requested_start_time = 12;
+
+    // The time at which the activity was first dispatched to a worker (i.e. when a worker first picked
+    // up the task from matching). Not set until a worker picks up the first attempt. Not updated on
+    // subsequent retry attempts.
+    google.protobuf.Timestamp actual_start_time = 13;
 }
 
 // CallbackInfo contains the state of an attached activity callback.