diff --git a/examples/js/vr/WebVR.js b/examples/js/vr/WebVR.js
index 076228143e0cf0c17b89cafe67d12685654f2217..301e35f9b209be68589cb2d4b823cc5d3f85ec44 100644
--- a/examples/js/vr/WebVR.js
+++ b/examples/js/vr/WebVR.js
@@ -99,7 +99,15 @@ THREE.WEBVR = {
 
 				if ( currentSession === null ) {
 
-					navigator.xr.requestSession( 'immersive-vr' ).then( onSessionStarted );
+					// WebXR's requestReferenceSpace only works if the corresponding feature
+					// was requested at session creation time. For simplicity, just ask for
+					// the interesting ones as optional features, but be aware that the
+					// requestReferenceSpace call will fail if it turns out to be unavailable.
+					// ('local' is always available for immersive sessions and doesn't need to
+					// be requested separately.)
+
+					var sessionInit = { optionalFeatures: [ 'local-floor', 'bounded-floor' ] };
+					navigator.xr.requestSession( 'immersive-vr', sessionInit ).then( onSessionStarted );
 
 				} else {
 
diff --git a/examples/jsm/vr/WebVR.js b/examples/jsm/vr/WebVR.js
index 1b93855157bb5a0b98e91a7d4f0c9ea36910f780..db8ef0bcad6ad8cdd477cb83f0cf830adc73b27c 100644
--- a/examples/jsm/vr/WebVR.js
+++ b/examples/jsm/vr/WebVR.js
@@ -14,7 +14,6 @@ var WEBVR = {
 		if ( options && options.referenceSpaceType ) {
 
 			renderer.vr.setReferenceSpaceType( options.referenceSpaceType );
-
 		}
 
 		function showEnterVR( device ) {
@@ -101,7 +100,15 @@ var WEBVR = {
 
 				if ( currentSession === null ) {
 
-					navigator.xr.requestSession( 'immersive-vr' ).then( onSessionStarted );
+					// WebXR's requestReferenceSpace only works if the corresponding feature
+					// was requested at session creation time. For simplicity, just ask for
+					// the interesting ones as optional features, but be aware that the
+					// requestReferenceSpace call will fail if it turns out to be unavailable.
+					// ('local' is always available for immersive sessions and doesn't need to
+					// be requested separately.)
+
+					var sessionInit = { optionalFeatures: [ 'local-floor', 'bounded-floor' ] };
+					navigator.xr.requestSession( 'immersive-vr', sessionInit ).then( onSessionStarted );
 
 				} else {