diff --git a/.changelog/5735.txt b/.changelog/5735.txt
new file mode 100644
index 00000000000..d822ff90e73
--- /dev/null
+++ b/.changelog/5735.txt
@@ -0,0 +1,3 @@
+```release-note:enhancement
+transfer: added attribute `subject_id` to data source `google_storage_transfer_project_service_account`
+```
diff --git a/google/data_source_google_storage_transfer_project_service_account.go b/google/data_source_google_storage_transfer_project_service_account.go
index df0152c9ba2..5562196b70a 100644
--- a/google/data_source_google_storage_transfer_project_service_account.go
+++ b/google/data_source_google_storage_transfer_project_service_account.go
@@ -2,6 +2,7 @@ package google
 
 import (
 	"fmt"
+
 	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema"
 )
 
@@ -18,6 +19,10 @@ func dataSourceGoogleStorageTransferProjectServiceAccount() *schema.Resource {
 				Optional: true,
 				Computed: true,
 			},
+			"subject_id": {
+				Type:     schema.TypeString,
+				Computed: true,
+			},
 		},
 	}
 }
@@ -43,6 +48,9 @@ func dataSourceGoogleStorageTransferProjectServiceAccountRead(d *schema.Resource
 	if err := d.Set("email", serviceAccount.AccountEmail); err != nil {
 		return fmt.Errorf("Error setting email: %s", err)
 	}
+	if err := d.Set("subject_id", serviceAccount.SubjectId); err != nil {
+		return fmt.Errorf("Error setting subject_id: %s", err)
+	}
 	if err := d.Set("project", project); err != nil {
 		return fmt.Errorf("Error setting project: %s", err)
 	}
diff --git a/google/data_source_google_storage_transfer_project_service_account_test.go b/google/data_source_google_storage_transfer_project_service_account_test.go
index d4d5cb63def..e1a7d790d86 100644
--- a/google/data_source_google_storage_transfer_project_service_account_test.go
+++ b/google/data_source_google_storage_transfer_project_service_account_test.go
@@ -20,6 +20,7 @@ func TestAccDataSourceGoogleStorageTransferProjectServiceAccount_basic(t *testin
 				Check: resource.ComposeTestCheckFunc(
 					resource.TestCheckResourceAttrSet(resourceName, "id"),
 					resource.TestCheckResourceAttrSet(resourceName, "email"),
+					resource.TestCheckResourceAttrSet(resourceName, "subject_id"),
 				),
 			},
 		},
diff --git a/website/docs/d/storage_transfer_project_service_account.html.markdown b/website/docs/d/storage_transfer_project_service_account.html.markdown
index 1d355e45322..071049b27a2 100644
--- a/website/docs/d/storage_transfer_project_service_account.html.markdown
+++ b/website/docs/d/storage_transfer_project_service_account.html.markdown
@@ -33,4 +33,5 @@ The following arguments are supported:
 
 The following attributes are exported:
 
-* `email` - Email address of the default service account used by Storage Transfer Jobs running in this project
+* `email` - Email address of the default service account used by Storage Transfer Jobs running in this project.
+* `subject_id` - Unique identifier for the service account.