diff --git a/packages/rum-core/src/browser/performanceObservable.ts b/packages/rum-core/src/browser/performanceObservable.ts
index 7585d9697f..9c6d17e467 100644
--- a/packages/rum-core/src/browser/performanceObservable.ts
+++ b/packages/rum-core/src/browser/performanceObservable.ts
@@ -59,6 +59,7 @@ export interface RumPerformanceResourceTiming {
   decodedBodySize: number
   encodedBodySize: number
   transferSize: number
+  nextHopProtocol?: string
   renderBlockingStatus?: string
   traceId?: string
   toJSON(): Omit<PerformanceEntry, 'toJSON'>
diff --git a/packages/rum-core/src/domain/resource/resourceCollection.spec.ts b/packages/rum-core/src/domain/resource/resourceCollection.spec.ts
index 76316b3563..e36417cb59 100644
--- a/packages/rum-core/src/domain/resource/resourceCollection.spec.ts
+++ b/packages/rum-core/src/domain/resource/resourceCollection.spec.ts
@@ -79,6 +79,7 @@ describe('resourceCollection', () => {
         download: jasmine.any(Object),
         first_byte: jasmine.any(Object),
         status_code: 200,
+        protocol: 'HTTP/1.0',
         render_blocking_status: 'blocking',
       },
       type: RumEventType.RESOURCE,
@@ -116,6 +117,7 @@ describe('resourceCollection', () => {
         duration: (100 * 1e6) as ServerDuration,
         method: 'GET',
         status_code: 200,
+        protocol: undefined,
         type: ResourceType.XHR,
         url: 'https://resource.com/valid',
       },
@@ -229,6 +231,7 @@ describe('resourceCollection', () => {
         duration: (100 * 1e6) as ServerDuration,
         method: 'GET',
         status_code: 200,
+        protocol: undefined,
         type: ResourceType.FETCH,
         url: 'https://resource.com/valid',
       },
diff --git a/packages/rum-core/src/domain/resource/resourceCollection.ts b/packages/rum-core/src/domain/resource/resourceCollection.ts
index cb5c2e171e..f3e7bb8a71 100644
--- a/packages/rum-core/src/domain/resource/resourceCollection.ts
+++ b/packages/rum-core/src/domain/resource/resourceCollection.ts
@@ -30,6 +30,7 @@ import {
   computeResourceEntryDuration,
   computeResourceEntryType,
   computeResourceEntrySize,
+  computeResourceEntryProtocol,
   isResourceEntryRequestType,
   isLongDataUrl,
   sanitizeDataUrl,
@@ -104,6 +105,7 @@ function processRequest(
         duration,
         method: request.method,
         status_code: request.status,
+        protocol: matchingTiming && computeResourceEntryProtocol(matchingTiming),
         url: isLongDataUrl(request.url) ? sanitizeDataUrl(request.url) : request.url,
       },
       type: RumEventType.RESOURCE as const,
@@ -152,6 +154,7 @@ function processResourceEntry(
         type,
         url: entry.name,
         status_code: discardZeroStatus(entry.responseStatus),
+        protocol: computeResourceEntryProtocol(entry),
       },
       type: RumEventType.RESOURCE as const,
       _dd: {
diff --git a/packages/rum-core/src/domain/resource/resourceUtils.ts b/packages/rum-core/src/domain/resource/resourceUtils.ts
index 0b9d5886cc..68571cf2e4 100644
--- a/packages/rum-core/src/domain/resource/resourceUtils.ts
+++ b/packages/rum-core/src/domain/resource/resourceUtils.ts
@@ -177,6 +177,15 @@ function formatTiming(origin: RelativeTime, start: RelativeTime, end: RelativeTi
   }
 }
 
+/**
+ * The 'nextHopProtocol' is an empty string for cross-origin resources without CORS headers,
+ * meaning the protocol is unknown, and we shouldn't report it.
+ * https://developer.mozilla.org/en-US/docs/Web/API/PerformanceResourceTiming/nextHopProtocol#cross-origin_resources
+ */
+export function computeResourceEntryProtocol(entry: RumPerformanceResourceTiming) {
+  return entry.nextHopProtocol === '' ? undefined : entry.nextHopProtocol
+}
+
 export function computeResourceEntrySize(entry: RumPerformanceResourceTiming) {
   // Make sure a request actually occurred
   if (entry.startTime < entry.responseStart) {
diff --git a/packages/rum-core/src/rawRumEvent.types.ts b/packages/rum-core/src/rawRumEvent.types.ts
index 29a57f3d95..15f545431c 100644
--- a/packages/rum-core/src/rawRumEvent.types.ts
+++ b/packages/rum-core/src/rawRumEvent.types.ts
@@ -48,6 +48,7 @@ export interface RawRumResourceEvent {
     ssl?: ResourceEntryDetailsElement
     first_byte?: ResourceEntryDetailsElement
     download?: ResourceEntryDetailsElement
+    protocol?: string
   }
   _dd: {
     trace_id?: string
diff --git a/packages/rum-core/src/rumEvent.types.ts b/packages/rum-core/src/rumEvent.types.ts
index c77a947b26..a927a5defa 100644
--- a/packages/rum-core/src/rumEvent.types.ts
+++ b/packages/rum-core/src/rumEvent.types.ts
@@ -702,6 +702,10 @@ export type RumResourceEvent = CommonProperties &
         readonly start: number
         [k: string]: unknown
       }
+      /**
+       * Network protocol used to fetch the resource (e.g., 'http/1.1', 'h2')
+       */
+      readonly protocol?: string
       /**
        * The provider for this resource
        */
diff --git a/packages/rum-core/test/fixtures.ts b/packages/rum-core/test/fixtures.ts
index 2b74b77f3d..346959ea49 100644
--- a/packages/rum-core/test/fixtures.ts
+++ b/packages/rum-core/test/fixtures.ts
@@ -259,6 +259,7 @@ export function createPerformanceEntry<T extends RumPerformanceEntryType>(
           secureConnectionStart: 200 as RelativeTime,
           startTime: 200 as RelativeTime,
           responseStatus: 200,
+          nextHopProtocol: 'HTTP/1.0',
         },
         overrides
       ) as EntryTypeToReturnType[T]
diff --git a/rum-events-format b/rum-events-format
index ba50d0c05d..e1c6dde379 160000
--- a/rum-events-format
+++ b/rum-events-format
@@ -1 +1 @@
-Subproject commit ba50d0c05dcdd374bb962f40fc8f82db992da319
+Subproject commit e1c6dde3793714453b5b49f17790a24e9ff9b77b