diff --git a/third_party/blink/public/mojom/use_counter/metrics/web_feature.mojom b/third_party/blink/public/mojom/use_counter/metrics/web_feature.mojom
index 18b386524eb966..01712ec9e9a98a 100644
--- a/third_party/blink/public/mojom/use_counter/metrics/web_feature.mojom
+++ b/third_party/blink/public/mojom/use_counter/metrics/web_feature.mojom
@@ -3792,6 +3792,8 @@ enum WebFeature {
   kContentDispositionInSvgUse = 4451,
   kSameDocumentCrossOriginInitiator = 4452,
   kServiceWorkerFetchHandlerModifiedAfterInitialization = 4453,
+  kServiceWorkerAddHandlerAfterInitialization = 4468,
+  kServiceWorkerSetAttributeHandlerAfterInitialization = 4469,
 
   // Add new features immediately above this line. Don't change assigned
   // numbers of any item, and don't reuse removed slots.
diff --git a/third_party/blink/renderer/modules/service_worker/service_worker_global_scope.cc b/third_party/blink/renderer/modules/service_worker/service_worker_global_scope.cc
index 0dc366b235dc9d..1db08bf3dbc6ad 100644
--- a/third_party/blink/renderer/modules/service_worker/service_worker_global_scope.cc
+++ b/third_party/blink/renderer/modules/service_worker/service_worker_global_scope.cc
@@ -695,6 +695,8 @@ bool ServiceWorkerGlobalScope::AddEventListenerInternal(
           this,
           WebFeature::kServiceWorkerFetchHandlerUpdateAfterInitialization);
     }
+    UseCounter::Count(this,
+                      WebFeature::kServiceWorkerAddHandlerAfterInitialization);
   }
   return WorkerGlobalScope::AddEventListenerInternal(event_type, listener,
                                                      options);
@@ -2645,10 +2647,14 @@ bool ServiceWorkerGlobalScope::SetAttributeEventListener(
     const AtomicString& event_type,
     EventListener* listener) {
   // Count the modification of fetch handlers after the initial evaluation.
-  if (did_evaluate_script_ && event_type == event_type_names::kFetch) {
+  if (did_evaluate_script_) {
+    if (event_type == event_type_names::kFetch) {
+      UseCounter::Count(
+          this,
+          WebFeature::kServiceWorkerFetchHandlerModifiedAfterInitialization);
+    }
     UseCounter::Count(
-        this,
-        WebFeature::kServiceWorkerFetchHandlerModifiedAfterInitialization);
+        this, WebFeature::kServiceWorkerSetAttributeHandlerAfterInitialization);
   }
   return WorkerGlobalScope::SetAttributeEventListener(event_type, listener);
 }
diff --git a/tools/metrics/histograms/enums.xml b/tools/metrics/histograms/enums.xml
index e1621de677fbb2..b9dc5462fc816e 100644
--- a/tools/metrics/histograms/enums.xml
+++ b/tools/metrics/histograms/enums.xml
@@ -41969,6 +41969,9 @@ Called by update_use_counter_feature_enum.py.-->
   <int value="4452" label="SameDocumentCrossOriginInitiator"/>
   <int value="4453"
       label="ServiceWorkerFetchHandlerModifiedAfterInitialization"/>
+  <int value="4468" label="ServiceWorkerAddHandlerAfterInitialization"/>
+  <int value="4469"
+      label="ServiceWorkerSetAttributeHandlerAfterInitialization"/>
 </enum>
 
 <enum name="FeaturePolicyAllowlistType">