diff --git a/packages/metro-bundler/src/DeltaBundler/Serializers.js b/packages/metro-bundler/src/DeltaBundler/Serializers.js
index 6db62ee4..b981914f 100644
--- a/packages/metro-bundler/src/DeltaBundler/Serializers.js
+++ b/packages/metro-bundler/src/DeltaBundler/Serializers.js
@@ -17,6 +17,7 @@ const DeltaPatcher = require('./DeltaPatcher');
 const {fromRawMappings} = require('../Bundler/source-map');
 
 import type {BundleOptions} from '../Server';
+import type {MappingsMap} from '../lib/SourceMap';
 import type DeltaBundler, {Options as BuildOptions} from './';
 import type {DeltaTransformResponse} from './DeltaTransformer';
 
@@ -73,6 +74,22 @@ async function fullSourceMap(
   });
 }
 
+async function fullSourceMapObject(
+  deltaBundler: DeltaBundler,
+  options: Options,
+): Promise<MappingsMap> {
+  const {id, delta} = await _build(deltaBundler, {
+    ...options,
+    wrapModules: true,
+  });
+
+  const deltaPatcher = DeltaPatcher.get(id).applyDelta(delta);
+
+  return fromRawMappings(deltaPatcher.getAllModules()).toMap(undefined, {
+    excludeSource: options.excludeSource,
+  });
+}
+
 /**
  * Returns the full JS bundle, which can be directly parsed by a JS interpreter
  */
@@ -113,4 +130,5 @@ module.exports = {
   deltaBundle,
   fullBundle,
   fullSourceMap,
+  fullSourceMapObject,
 };
diff --git a/packages/metro-bundler/src/Server/index.js b/packages/metro-bundler/src/Server/index.js
index b6b4cd4b..bd66ca1d 100644
--- a/packages/metro-bundler/src/Server/index.js
+++ b/packages/metro-bundler/src/Server/index.js
@@ -1142,8 +1142,16 @@ class Server {
       );
   }
 
-  _sourceMapForURL(reqUrl: string): Promise<SourceMap> {
-    const options = this._getOptionsFromUrl(reqUrl);
+  async _sourceMapForURL(reqUrl: string): Promise<SourceMap> {
+    const options: DeltaBundlerOptions = this._getOptionsFromUrl(reqUrl);
+
+    if (this._opts.useDeltaBundler) {
+      return await Serializers.fullSourceMapObject(this._deltaBundler, {
+        ...options,
+        deltaBundleId: this.optionsHash(options),
+      });
+    }
+
     // We're not properly reporting progress here. Reporting should be done
     // from within that function.
     const building = this.useCachedOrUpdateOrCreateBundle(