diff --git a/rmw_fastrtps_cpp/src/rmw_publisher.cpp b/rmw_fastrtps_cpp/src/rmw_publisher.cpp
index 3d1cfe8f5..10fd5e3b2 100644
--- a/rmw_fastrtps_cpp/src/rmw_publisher.cpp
+++ b/rmw_fastrtps_cpp/src/rmw_publisher.cpp
@@ -150,6 +150,23 @@ rmw_publisher_count_matched_subscriptions(
     publisher, subscription_count);
 }
 
+rmw_ret_t
+rmw_publisher_count_non_local_matched_subscriptions(
+  const rmw_publisher_t * publisher,
+  size_t * non_local_subscription_count)
+{
+  RMW_CHECK_ARGUMENT_FOR_NULL(publisher, RMW_RET_INVALID_ARGUMENT);
+  RMW_CHECK_TYPE_IDENTIFIERS_MATCH(
+    publisher,
+    publisher->implementation_identifier,
+    eprosima_fastrtps_identifier,
+    return RMW_RET_INCORRECT_RMW_IMPLEMENTATION);
+  RMW_CHECK_ARGUMENT_FOR_NULL(non_local_subscription_count, RMW_RET_INVALID_ARGUMENT);
+
+  return rmw_fastrtps_shared_cpp::__rmw_publisher_count_non_local_matched_subscriptions(
+    publisher, non_local_subscription_count);
+}
+
 rmw_ret_t
 rmw_publisher_assert_liveliness(const rmw_publisher_t * publisher)
 {
diff --git a/rmw_fastrtps_dynamic_cpp/src/rmw_publisher.cpp b/rmw_fastrtps_dynamic_cpp/src/rmw_publisher.cpp
index c5b1ca459..d7b6b9cc8 100644
--- a/rmw_fastrtps_dynamic_cpp/src/rmw_publisher.cpp
+++ b/rmw_fastrtps_dynamic_cpp/src/rmw_publisher.cpp
@@ -150,6 +150,23 @@ rmw_publisher_count_matched_subscriptions(
     publisher, subscription_count);
 }
 
+rmw_ret_t
+rmw_publisher_count_non_local_matched_subscriptions(
+  const rmw_publisher_t * publisher,
+  size_t * non_local_subscription_count)
+{
+  RMW_CHECK_ARGUMENT_FOR_NULL(publisher, RMW_RET_INVALID_ARGUMENT);
+  RMW_CHECK_TYPE_IDENTIFIERS_MATCH(
+    publisher,
+    publisher->implementation_identifier,
+    eprosima_fastrtps_identifier,
+    return RMW_RET_INCORRECT_RMW_IMPLEMENTATION);
+  RMW_CHECK_ARGUMENT_FOR_NULL(non_local_subscription_count, RMW_RET_INVALID_ARGUMENT);
+
+  return rmw_fastrtps_shared_cpp::__rmw_publisher_count_non_local_matched_subscriptions(
+    publisher, non_local_subscription_count);
+}
+
 rmw_ret_t
 rmw_publisher_assert_liveliness(const rmw_publisher_t * publisher)
 {
diff --git a/rmw_fastrtps_shared_cpp/include/rmw_fastrtps_shared_cpp/custom_publisher_info.hpp b/rmw_fastrtps_shared_cpp/include/rmw_fastrtps_shared_cpp/custom_publisher_info.hpp
index f3023f72b..cf339ef66 100644
--- a/rmw_fastrtps_shared_cpp/include/rmw_fastrtps_shared_cpp/custom_publisher_info.hpp
+++ b/rmw_fastrtps_shared_cpp/include/rmw_fastrtps_shared_cpp/custom_publisher_info.hpp
@@ -120,9 +120,10 @@ class RMWPublisherEvent final : public EventListenerInterface
    * user calls rmw_count_subscribers().
    *
    * \param[in] guid The GUID of the newly-matched subscription to track.
+   * \param[in] is_local Whether \c guid belongs to the same participant as this publisher.
    */
   RMW_FASTRTPS_SHARED_CPP_PUBLIC
-  void track_unique_subscription(eprosima::fastrtps::rtps::GUID_t guid);
+  void track_unique_subscription(eprosima::fastrtps::rtps::GUID_t guid, bool is_local);
 
   /// Remove a GUID from the internal set of unique subscriptions matched to this publisher.
   /**
@@ -130,9 +131,10 @@ class RMWPublisherEvent final : public EventListenerInterface
    * user calls rmw_count_subscribers().
    *
    * \param[in] guid The GUID of the newly-unmatched subscription to track.
+   * \param[in] is_local Whether \c guid belongs to the same participant as this publisher.
    */
   RMW_FASTRTPS_SHARED_CPP_PUBLIC
-  void untrack_unique_subscription(eprosima::fastrtps::rtps::GUID_t guid);
+  void untrack_unique_subscription(eprosima::fastrtps::rtps::GUID_t guid, bool is_local);
 
   /// Return the number of unique subscriptions matched to this publisher.
   /**
@@ -141,6 +143,13 @@ class RMWPublisherEvent final : public EventListenerInterface
   RMW_FASTRTPS_SHARED_CPP_PUBLIC
   size_t subscription_count() const;
 
+  /// Return the number of unique non-local subscriptions matched to this publisher.
+  /**
+   * \return Number of unique non-local subscriptions matched to this publisher.
+   */
+  RMW_FASTRTPS_SHARED_CPP_PUBLIC
+  size_t non_local_subscription_count() const;
+
   RMW_FASTRTPS_SHARED_CPP_PUBLIC
   void update_deadline(uint32_t total_count, uint32_t total_count_change);
 
@@ -165,6 +174,9 @@ class RMWPublisherEvent final : public EventListenerInterface
   std::set<eprosima::fastrtps::rtps::GUID_t> subscriptions_
   RCPPUTILS_TSA_GUARDED_BY(subscriptions_mutex_);
 
+  std::set<eprosima::fastrtps::rtps::GUID_t> non_local_subscriptions_
+  RCPPUTILS_TSA_GUARDED_BY(subscriptions_mutex_);
+
   mutable std::mutex subscriptions_mutex_;
 
   bool deadline_changed_
diff --git a/rmw_fastrtps_shared_cpp/include/rmw_fastrtps_shared_cpp/rmw_common.hpp b/rmw_fastrtps_shared_cpp/include/rmw_fastrtps_shared_cpp/rmw_common.hpp
index 2994c108f..b693bc5fa 100644
--- a/rmw_fastrtps_shared_cpp/include/rmw_fastrtps_shared_cpp/rmw_common.hpp
+++ b/rmw_fastrtps_shared_cpp/include/rmw_fastrtps_shared_cpp/rmw_common.hpp
@@ -217,6 +217,12 @@ __rmw_publisher_count_matched_subscriptions(
   const rmw_publisher_t * publisher,
   size_t * subscription_count);
 
+RMW_FASTRTPS_SHARED_CPP_PUBLIC
+rmw_ret_t
+__rmw_publisher_count_non_local_matched_subscriptions(
+  const rmw_publisher_t * publisher,
+  size_t * non_local_subscription_count);
+
 RMW_FASTRTPS_SHARED_CPP_PUBLIC
 rmw_ret_t
 __rmw_publisher_get_actual_qos(
diff --git a/rmw_fastrtps_shared_cpp/src/custom_publisher_info.cpp b/rmw_fastrtps_shared_cpp/src/custom_publisher_info.cpp
index f6d4cfbe8..36c53c4c0 100644
--- a/rmw_fastrtps_shared_cpp/src/custom_publisher_info.cpp
+++ b/rmw_fastrtps_shared_cpp/src/custom_publisher_info.cpp
@@ -38,14 +38,14 @@ void CustomDataWriterListener::on_publication_matched(
   eprosima::fastdds::dds::DataWriter * writer,
   const eprosima::fastdds::dds::PublicationMatchedStatus & status)
 {
-  (void)writer;
+  eprosima::fastrtps::rtps::GUID_t subscription_guid =
+    eprosima::fastrtps::rtps::iHandle2GUID(status.last_subscription_handle);
+  bool is_local = writer->guid().guidPrefix == subscription_guid.guidPrefix;
 
   if (status.current_count_change == 1) {
-    publisher_event_->track_unique_subscription(
-      eprosima::fastrtps::rtps::iHandle2GUID(status.last_subscription_handle));
+    publisher_event_->track_unique_subscription(subscription_guid, is_local);
   } else if (status.current_count_change == -1) {
-    publisher_event_->untrack_unique_subscription(
-      eprosima::fastrtps::rtps::iHandle2GUID(status.last_subscription_handle));
+    publisher_event_->untrack_unique_subscription(subscription_guid, is_local);
   } else {
     return;
   }
@@ -277,16 +277,26 @@ void RMWPublisherEvent::set_on_new_event_callback(
   publisher_info_->data_writer_->set_listener(publisher_info_->data_writer_listener_, status_mask);
 }
 
-void RMWPublisherEvent::track_unique_subscription(eprosima::fastrtps::rtps::GUID_t guid)
+void RMWPublisherEvent::track_unique_subscription(
+  eprosima::fastrtps::rtps::GUID_t guid,
+  bool is_local)
 {
   std::lock_guard<std::mutex> lock(subscriptions_mutex_);
   subscriptions_.insert(guid);
+  if (!is_local) {
+    non_local_subscriptions_.insert(guid);
+  }
 }
 
-void RMWPublisherEvent::untrack_unique_subscription(eprosima::fastrtps::rtps::GUID_t guid)
+void RMWPublisherEvent::untrack_unique_subscription(
+  eprosima::fastrtps::rtps::GUID_t guid,
+  bool is_local)
 {
   std::lock_guard<std::mutex> lock(subscriptions_mutex_);
   subscriptions_.erase(guid);
+  if (!is_local) {
+    non_local_subscriptions_.erase(guid);
+  }
 }
 
 size_t RMWPublisherEvent::subscription_count() const
@@ -295,6 +305,12 @@ size_t RMWPublisherEvent::subscription_count() const
   return subscriptions_.size();
 }
 
+size_t RMWPublisherEvent::non_local_subscription_count() const
+{
+  std::lock_guard<std::mutex> lock(subscriptions_mutex_);
+  return non_local_subscriptions_.size();
+}
+
 void RMWPublisherEvent::update_deadline(uint32_t total_count, uint32_t total_count_change)
 {
   rcpputils::unique_lock<std::mutex> lock_mutex(on_new_event_m_);
diff --git a/rmw_fastrtps_shared_cpp/src/rmw_publisher.cpp b/rmw_fastrtps_shared_cpp/src/rmw_publisher.cpp
index 8ad697aba..e08c56018 100644
--- a/rmw_fastrtps_shared_cpp/src/rmw_publisher.cpp
+++ b/rmw_fastrtps_shared_cpp/src/rmw_publisher.cpp
@@ -99,6 +99,18 @@ __rmw_publisher_count_matched_subscriptions(
   return RMW_RET_OK;
 }
 
+rmw_ret_t
+__rmw_publisher_count_non_local_matched_subscriptions(
+  const rmw_publisher_t * publisher,
+  size_t * non_local_subscription_count)
+{
+  auto info = static_cast<CustomPublisherInfo *>(publisher->data);
+
+  *non_local_subscription_count = info->publisher_event_->non_local_subscription_count();
+
+  return RMW_RET_OK;
+}
+
 rmw_ret_t
 __rmw_publisher_assert_liveliness(
   const char * identifier,