diff --git a/packages/service-worker/rollup.config.js b/packages/service-worker/rollup.config.js
index 00d9ea89e0..6242de44c3 100644
--- a/packages/service-worker/rollup.config.js
+++ b/packages/service-worker/rollup.config.js
@@ -21,6 +21,7 @@ const globals = {
   'rxjs/observable/defer': 'Rx.Observable',
   'rxjs/observable/fromEvent': 'Rx.Observable',
   'rxjs/observable/merge': 'Rx.Observable',
+  'rxjs/observable/never': 'Rx.Observable',
   'rxjs/observable/of': 'Rx.Observable',
   'rxjs/observable/throw': 'Rx.Observable',
 
diff --git a/packages/service-worker/src/low_level.ts b/packages/service-worker/src/low_level.ts
index 1632ca6bbd..6d46b7264a 100644
--- a/packages/service-worker/src/low_level.ts
+++ b/packages/service-worker/src/low_level.ts
@@ -24,7 +24,7 @@ import {switchMap as op_switchMap} from 'rxjs/operator/switchMap';
 import {take as op_take} from 'rxjs/operator/take';
 import {toPromise as op_toPromise} from 'rxjs/operator/toPromise';
 
-const ERR_SW_NOT_SUPPORTED = 'Service workers are not supported by this browser';
+export const ERR_SW_NOT_SUPPORTED = 'Service workers are disabled or not supported by this browser';
 
 export interface Version {
   hash: string;
@@ -86,9 +86,9 @@ export class NgswCommChannel {
    */
   readonly events: Observable<IncomingEvent>;
 
-  constructor(serviceWorker: ServiceWorkerContainer|undefined) {
+  constructor(private serviceWorker: ServiceWorkerContainer|undefined) {
     if (!serviceWorker) {
-      this.worker = this.events = errorObservable(ERR_SW_NOT_SUPPORTED);
+      this.worker = this.events = this.registration = errorObservable(ERR_SW_NOT_SUPPORTED);
     } else {
       const controllerChangeEvents =
           <Observable<any>>(obs_fromEvent(serviceWorker, 'controllerchange'));
@@ -176,4 +176,6 @@ export class NgswCommChannel {
         }));
     return op_toPromise.call(mapErrorAndValue);
   }
+
+  get isEnabled(): boolean { return !!this.serviceWorker; }
 }
\ No newline at end of file
diff --git a/packages/service-worker/src/push.ts b/packages/service-worker/src/push.ts
index 845a886207..7300376433 100644
--- a/packages/service-worker/src/push.ts
+++ b/packages/service-worker/src/push.ts
@@ -9,15 +9,15 @@
 import {Injectable} from '@angular/core';
 import {Observable} from 'rxjs/Observable';
 import {Subject} from 'rxjs/Subject';
-
 import {merge as obs_merge} from 'rxjs/observable/merge';
-
+import {never as obs_never} from 'rxjs/observable/never';
 import {map as op_map} from 'rxjs/operator/map';
 import {switchMap as op_switchMap} from 'rxjs/operator/switchMap';
 import {take as op_take} from 'rxjs/operator/take';
 import {toPromise as op_toPromise} from 'rxjs/operator/toPromise';
 
-import {NgswCommChannel} from './low_level';
+import {ERR_SW_NOT_SUPPORTED, NgswCommChannel} from './low_level';
+
 
 /**
  * Subscribe and listen to push notifications from the Service Worker.
@@ -34,6 +34,11 @@ export class SwPush {
       new Subject<PushSubscription|null>();
 
   constructor(private sw: NgswCommChannel) {
+    if (!sw.isEnabled) {
+      this.messages = obs_never();
+      this.subscription = obs_never();
+      return;
+    }
     this.messages =
         op_map.call(this.sw.eventsOfType('PUSH'), (message: {data: object}) => message.data);
 
@@ -46,7 +51,16 @@ export class SwPush {
     this.subscription = obs_merge(workerDrivenSubscriptions, this.subscriptionChanges);
   }
 
+  /**
+   * Returns true if the Service Worker is enabled (supported by the browser and enabled via
+   * ServiceWorkerModule).
+   */
+  get isEnabled(): boolean { return this.sw.isEnabled; }
+
   requestSubscription(options: {serverPublicKey: string}): Promise<PushSubscription> {
+    if (!this.sw.isEnabled) {
+      return Promise.reject(new Error(ERR_SW_NOT_SUPPORTED));
+    }
     const pushOptions: PushSubscriptionOptionsInit = {userVisibleOnly: true};
     let key = atob(options.serverPublicKey.replace(/_/g, '/').replace(/-/g, '+'));
     let applicationServerKey = new Uint8Array(new ArrayBuffer(key.length));
@@ -64,6 +78,9 @@ export class SwPush {
   }
 
   unsubscribe(): Promise<void> {
+    if (!this.sw.isEnabled) {
+      return Promise.reject(new Error(ERR_SW_NOT_SUPPORTED));
+    }
     const unsubscribe = op_switchMap.call(this.subscription, (sub: PushSubscription | null) => {
       if (sub !== null) {
         return sub.unsubscribe().then(success => {
diff --git a/packages/service-worker/src/update.ts b/packages/service-worker/src/update.ts
index 349f526fe8..d2f1a80e84 100644
--- a/packages/service-worker/src/update.ts
+++ b/packages/service-worker/src/update.ts
@@ -9,9 +9,10 @@
 import {Injectable} from '@angular/core';
 import {Observable} from 'rxjs/Observable';
 import {defer as obs_defer} from 'rxjs/observable/defer';
+import {never as obs_never} from 'rxjs/observable/never';
 import {map as op_map} from 'rxjs/operator/map';
 
-import {NgswCommChannel, UpdateActivatedEvent, UpdateAvailableEvent} from './low_level';
+import {ERR_SW_NOT_SUPPORTED, NgswCommChannel, UpdateActivatedEvent, UpdateAvailableEvent} from './low_level';
 
 
 /**
@@ -26,16 +27,33 @@ export class SwUpdate {
   readonly activated: Observable<UpdateActivatedEvent>;
 
   constructor(private sw: NgswCommChannel) {
+    if (!sw.isEnabled) {
+      this.available = obs_never();
+      this.activated = obs_never();
+      return;
+    }
     this.available = this.sw.eventsOfType('UPDATE_AVAILABLE');
     this.activated = this.sw.eventsOfType('UPDATE_ACTIVATED');
   }
 
+  /**
+   * Returns true if the Service Worker is enabled (supported by the browser and enabled via
+   * ServiceWorkerModule).
+   */
+  get isEnabled(): boolean { return this.sw.isEnabled; }
+
   checkForUpdate(): Promise<void> {
+    if (!this.sw.isEnabled) {
+      return Promise.reject(new Error(ERR_SW_NOT_SUPPORTED));
+    }
     const statusNonce = this.sw.generateNonce();
     return this.sw.postMessageWithStatus('CHECK_FOR_UPDATES', {statusNonce}, statusNonce);
   }
 
   activateUpdate(): Promise<void> {
+    if (!this.sw.isEnabled) {
+      return Promise.reject(new Error(ERR_SW_NOT_SUPPORTED));
+    }
     const statusNonce = this.sw.generateNonce();
     return this.sw.postMessageWithStatus('ACTIVATE_UPDATE', {statusNonce}, statusNonce);
   }
diff --git a/packages/service-worker/test/comm_spec.ts b/packages/service-worker/test/comm_spec.ts
index c1c0d75c80..9788c9b1a7 100644
--- a/packages/service-worker/test/comm_spec.ts
+++ b/packages/service-worker/test/comm_spec.ts
@@ -71,6 +71,24 @@ export function main() {
         });
         expect(() => TestBed.get(SwPush)).not.toThrow();
       });
+      describe('with no SW', () => {
+        beforeEach(() => { comm = new NgswCommChannel(undefined); });
+        it('can be instantiated', () => { push = new SwPush(comm); });
+        it('does not crash on subscription to observables', () => {
+          push = new SwPush(comm);
+          push.messages.toPromise().catch(err => fail(err));
+          push.subscription.toPromise().catch(err => fail(err));
+        });
+        it('gives an error when registering', done => {
+          push = new SwPush(comm);
+          push.requestSubscription({serverPublicKey: 'test'}).catch(err => { done(); });
+        });
+        it('gives an error when unsubscribing', done => {
+
+          push = new SwPush(comm);
+          push.unsubscribe().catch(err => { done(); });
+        });
+      });
     });
     describe('SwUpdate', () => {
       let update: SwUpdate;
@@ -147,6 +165,23 @@ export function main() {
         });
         expect(() => TestBed.get(SwUpdate)).not.toThrow();
       });
+      describe('with no SW', () => {
+        beforeEach(() => { comm = new NgswCommChannel(undefined); });
+        it('can be instantiated', () => { update = new SwUpdate(comm); });
+        it('does not crash on subscription to observables', () => {
+          update = new SwUpdate(comm);
+          update.available.toPromise().catch(err => fail(err));
+          update.activated.toPromise().catch(err => fail(err));
+        });
+        it('gives an error when checking for updates', done => {
+          update = new SwUpdate(comm);
+          update.checkForUpdate().catch(err => { done(); });
+        });
+        it('gives an error when activating updates', done => {
+          update = new SwUpdate(comm);
+          update.activateUpdate().catch(err => { done(); });
+        });
+      });
     });
   });
 }
diff --git a/tools/public_api_guard/service-worker/service-worker.d.ts b/tools/public_api_guard/service-worker/service-worker.d.ts
index c70daacd72..e05787c01a 100644
--- a/tools/public_api_guard/service-worker/service-worker.d.ts
+++ b/tools/public_api_guard/service-worker/service-worker.d.ts
@@ -8,6 +8,7 @@ export declare class ServiceWorkerModule {
 
 /** @experimental */
 export declare class SwPush {
+    readonly isEnabled: boolean;
     readonly messages: Observable<object>;
     readonly subscription: Observable<PushSubscription | null>;
     constructor(sw: NgswCommChannel);
@@ -21,6 +22,7 @@ export declare class SwPush {
 export declare class SwUpdate {
     readonly activated: Observable<UpdateActivatedEvent>;
     readonly available: Observable<UpdateAvailableEvent>;
+    readonly isEnabled: boolean;
     constructor(sw: NgswCommChannel);
     activateUpdate(): Promise<void>;
     checkForUpdate(): Promise<void>;