--- a/mobile/android/app/src/main/res/xml/preferences_advanced.xml
+++ b/mobile/android/app/src/main/res/xml/preferences_advanced.xml
@@ -73,21 +73,16 @@
                                                                 android:persistent="false"
                                                                 url="https://developer.mozilla.org/docs/Tools/Remote_Debugging/Debugging_Firefox_for_Android_with_WebIDE" />
     </PreferenceCategory>
 
     <PreferenceCategory
         android:key="android.not_a_preference.category_experimental"
         android:title="@string/pref_category_experimental">
 
-        <SwitchPreference android:key="android.not_a_preference.customtabs"
-            android:title="@string/pref_custom_tabs"
-            android:summary="@string/pref_custom_tabs_summary"
-            android:defaultValue="false" />
-
         <SwitchPreference android:key="android.not_a_preference.pwa"
             android:title="@string/pref_pwa"
             android:summary="@string/pref_pwa_summary"
             android:defaultValue="false" />
 
     </PreferenceCategory>
 
 </PreferenceScreen>

--- a/mobile/android/base/AndroidManifest.xml.in
+++ b/mobile/android/base/AndroidManifest.xml.in
@@ -307,22 +307,20 @@
             <intent-filter>
                 <action android:name="android.intent.action.SEND" />
                 <category android:name="android.intent.category.DEFAULT" />
                 <data android:mimeType="text/plain" />
             </intent-filter>
 
         </activity>
 
-#ifdef MOZ_ANDROID_CUSTOM_TABS
         <activity android:name="org.mozilla.gecko.customtabs.CustomTabsActivity"
                   android:configChanges="keyboard|keyboardHidden|mcc|mnc|orientation|screenSize|locale|layoutDirection|smallestScreenSize|screenLayout"
                   android:windowSoftInputMode="stateUnspecified|adjustResize"
                   android:theme="@style/GeckoCustomTabs" />
-#endif
 
         <activity android:name="org.mozilla.gecko.webapps.WebAppActivity"
             android:theme="@style/Theme.AppCompat.NoActionBar" />
 
         <!-- Declare a predefined number of WebApp<num> activities. These are
              used so that each web app can launch in its own activity. -->
 #define FRAGMENT WebAppManifestFragment.xml.frag.in
 #include WebAppFragmentRepeater.inc
@@ -399,25 +397,23 @@
                 <action android:name="android.intent.action.MY_PACKAGE_REPLACED"></action>
             </intent-filter>
         </receiver>
 
         <service
           android:name="org.mozilla.gecko.telemetry.TelemetryUploadService"
           android:exported="false"/>
 
-#ifdef MOZ_ANDROID_CUSTOM_TABS
         <service
             android:name="org.mozilla.gecko.customtabs.GeckoCustomTabsService"
             android:exported="true">
             <intent-filter>
                 <action android:name="android.support.customtabs.action.CustomTabsService" />
             </intent-filter>
         </service>
-#endif
 
 #include ../services/manifests/FxAccountAndroidManifest_services.xml.in
 
         <service
             android:name="org.mozilla.gecko.tabqueue.TabReceivedService"
             android:exported="false" />
 
 

--- a/mobile/android/base/AppConstants.java.in
+++ b/mobile/android/base/AppConstants.java.in
@@ -300,23 +300,16 @@ public class AppConstants {
 
     public static final boolean MOZ_ANDROID_DOWNLOAD_CONTENT_SERVICE =
 //#ifdef MOZ_ANDROID_DOWNLOAD_CONTENT_SERVICE
     true;
 //#else
     false;
 //#endif
 
-    public static final boolean MOZ_ANDROID_CUSTOM_TABS =
-//#ifdef MOZ_ANDROID_CUSTOM_TABS
-    true;
-//#else
-    false;
-//#endif
-
     public static final boolean MOZ_ANDROID_PWA =
 //#ifdef MOZ_ANDROID_PWA
     true;
 //#else
     false;
 //#endif
 
     // (bug 1266820) Temporarily disabled since no one is working on it.

--- a/mobile/android/base/generate_build_config.py
+++ b/mobile/android/base/generate_build_config.py
@@ -34,17 +34,16 @@ from mozbuild.android_version_code impor
 def _defines():
     CONFIG = defaultdict(lambda: None)
     CONFIG.update(buildconfig.substs)
     DEFINES = dict(buildconfig.defines)
 
     for var in ('MOZ_ANDROID_ACTIVITY_STREAM'
                 'MOZ_ANDROID_ANR_REPORTER',
                 'MOZ_ANDROID_BEAM',
-                'MOZ_ANDROID_CUSTOM_TABS',
                 'MOZ_ANDROID_DOWNLOADS_INTEGRATION',
                 'MOZ_ANDROID_DOWNLOAD_CONTENT_SERVICE',
                 'MOZ_ANDROID_EXCLUDE_FONTS',
                 'MOZ_ANDROID_GCM',
                 'MOZ_ANDROID_MLS_STUMBLER',
                 'MOZ_ANDROID_MMA',
                 'MOZ_ANDROID_MOZILLA_ONLINE',
                 'MOZ_ANDROID_POCKET',

--- a/mobile/android/base/java/org/mozilla/gecko/LauncherActivity.java
+++ b/mobile/android/base/java/org/mozilla/gecko/LauncherActivity.java
@@ -65,19 +65,17 @@ public class LauncherActivity extends Ac
         // Is this web app?
         } else if (isWebAppIntent(safeIntent)) {
             dispatchWebAppIntent();
 
         // If it's not a view intent, it won't be a custom tabs intent either. Just launch!
         } else if (!isViewIntentWithURL(safeIntent)) {
             dispatchNormalIntent();
 
-        // Is this a custom tabs intent, and are custom tabs enabled?
-        } else if (AppConstants.MOZ_ANDROID_CUSTOM_TABS && isCustomTabsIntent(safeIntent)
-                && isCustomTabsEnabled()) {
+        } else if (isCustomTabsIntent(safeIntent)) {
             dispatchCustomTabsIntent();
 
         // Can we dispatch this VIEW action intent to the tab queue service?
         } else if (!safeIntent.getBooleanExtra(BrowserContract.SKIP_TAB_QUEUE_FLAG, false)
                 && TabQueueHelper.TAB_QUEUE_ENABLED
                 && TabQueueHelper.isTabQueueEnabled(this)) {
             dispatchTabQueueIntent();
 
@@ -165,20 +163,16 @@ public class LauncherActivity extends Ac
         return isViewIntentWithURL(safeIntent)
                 && safeIntent.hasExtra(CustomTabsIntent.EXTRA_SESSION);
     }
 
     private static boolean isWebAppIntent(@NonNull final SafeIntent safeIntent) {
         return GeckoApp.ACTION_WEBAPP.equals(safeIntent.getAction());
     }
 
-    private boolean isCustomTabsEnabled() {
-        return GeckoSharedPrefs.forApp(this).getBoolean(GeckoPreferences.PREFS_CUSTOM_TABS, false);
-    }
-
     private static boolean isShutdownIntent(@NonNull final SafeIntent safeIntent) {
         return GeckoApp.ACTION_SHUTDOWN.equals(safeIntent.getAction());
     }
 
     private boolean isDeepLink(SafeIntent intent) {
         if (intent == null || intent.getData() == null || intent.getData().getScheme() == null
                 || intent.getAction() == null) {
             return false;

--- a/mobile/android/base/java/org/mozilla/gecko/preferences/GeckoPreferences.java
+++ b/mobile/android/base/java/org/mozilla/gecko/preferences/GeckoPreferences.java
@@ -144,17 +144,16 @@ public class GeckoPreferences
     public static final String PREFS_HOMEPAGE_PARTNER_COPY = GeckoPreferences.PREFS_HOMEPAGE + ".partner";
     public static final String PREFS_HISTORY_SAVED_SEARCH = NON_PREF_PREFIX + "search.search_history.enabled";
     private static final String PREFS_FAQ_LINK = NON_PREF_PREFIX + "faq.link";
     private static final String PREFS_FEEDBACK_LINK = NON_PREF_PREFIX + "feedback.link";
     public static final String PREFS_NOTIFICATIONS_WHATS_NEW = NON_PREF_PREFIX + "notifications.whats_new";
     public static final String PREFS_APP_UPDATE_LAST_BUILD_ID = "app.update.last_build_id";
     public static final String PREFS_READ_PARTNER_CUSTOMIZATIONS_PROVIDER = NON_PREF_PREFIX + "distribution.read_partner_customizations_provider";
     public static final String PREFS_READ_PARTNER_BOOKMARKS_PROVIDER = NON_PREF_PREFIX + "distribution.read_partner_bookmarks_provider";
-    public static final String PREFS_CUSTOM_TABS = NON_PREF_PREFIX + "customtabs";
     public static final String PREFS_PWA = NON_PREF_PREFIX + "pwa";
     public static final String PREFS_CATEGORY_EXPERIMENTAL_FEATURES = NON_PREF_PREFIX + "category_experimental";
     public static final String PREFS_COMPACT_TABS = NON_PREF_PREFIX + "compact_tabs";
     public static final String PREFS_SHOW_QUIT_MENU = NON_PREF_PREFIX + "distribution.show_quit_menu";
     public static final String PREFS_SEARCH_SUGGESTIONS_ENABLED = "browser.search.suggest.enabled";
     public static final String PREFS_DEFAULT_BROWSER = NON_PREF_PREFIX + "default_browser.link";
     public static final String PREFS_SYSTEM_FONT_SIZE = NON_PREF_PREFIX + "font.size.use_system_font_size";
     public static final String PREFS_SET_AS_HOMEPAGE = NON_PREF_PREFIX + "distribution.set_as_homepage";
@@ -641,18 +640,17 @@ public class GeckoPreferences
                         continue;
                     }
                 } else if (PREFS_SCREEN_ADVANCED.equals(key) &&
                         !Restrictions.isAllowed(this, Restrictable.ADVANCED_SETTINGS)) {
                     preferences.removePreference(pref);
                     i--;
                     continue;
                 } else if (PREFS_CATEGORY_EXPERIMENTAL_FEATURES.equals(key)
-                        && !AppConstants.MOZ_ANDROID_PWA
-                        && !AppConstants.MOZ_ANDROID_CUSTOM_TABS) {
+                        && !AppConstants.MOZ_ANDROID_PWA) {
                     preferences.removePreference(pref);
                     i--;
                     continue;
                 }
                 setupPreferences((PreferenceGroup) pref, prefs);
             } else {
                 if (HANDLERS.containsKey(key)) {
                     PrefHandler handler = HANDLERS.get(key);
@@ -805,20 +803,16 @@ public class GeckoPreferences
                     final String url = getResources().getString(R.string.feedback_link, AppConstants.MOZ_APP_VERSION, AppConstants.MOZ_UPDATE_CHANNEL);
                     ((LinkPreference) pref).setUrl(url);
                 } else if (PREFS_DYNAMIC_TOOLBAR.equals(key)) {
                     if (DynamicToolbar.isForceDisabled()) {
                         preferences.removePreference(pref);
                         i--;
                         continue;
                     }
-                } else if (PREFS_CUSTOM_TABS.equals(key) && !AppConstants.MOZ_ANDROID_CUSTOM_TABS) {
-                    preferences.removePreference(pref);
-                    i--;
-                    continue;
                 } else if (PREFS_PWA.equals(key) && !AppConstants.MOZ_ANDROID_PWA) {
                     preferences.removePreference(pref);
                     i--;
                     continue;
                 } else if (PREFS_COMPACT_TABS.equals(key)) {
                     if (HardwareUtils.isTablet()) {
                         preferences.removePreference(pref);
                         i--;

--- a/mobile/android/base/locales/en-US/android_strings.dtd
+++ b/mobile/android/base/locales/en-US/android_strings.dtd
@@ -280,21 +280,16 @@
 
 <!ENTITY pref_whats_new_notification "What\'s new in &brandShortName;">
 <!ENTITY pref_whats_new_notification_summary "Learn about new features after an update">
 
 <!-- Localization note (pref_category_experimental): Title of a sub category in the 'advanced' category
      for experimental features. -->
 <!ENTITY pref_category_experimental "Experimental features">
 
-<!-- Custom Tabs is an Android API for allowing third-party apps to open URLs in a customized UI.
-     Instead of switching to the browser it appears as if the user stays in the third-party app.
-     For more see: https://developer.chrome.com/multidevice/android/customtabs -->
-<!ENTITY pref_custom_tabs "Custom Tabs">
-<!ENTITY pref_custom_tabs_summary3 "Allow apps to open websites using a customized version of &brandShortName;">
 <!-- Localization note (custom_tabs_menu_item_open_in): The variable is replaced by the name of
      default browser from user's preference, such as "Open in Firefox" -->
 <!ENTITY custom_tabs_menu_item_open_in "Open in &formatS;">
 <!ENTITY custom_tabs_menu_footer "Powered by &brandShortName;">
 <!-- Long-click title of CustomTabsActivity will copy URL to clipboard and display this hint -->
 <!ENTITY custom_tabs_hint_url_copy "URL copied">
 
 <!ENTITY pref_pwa "Progressive Web Apps">

--- a/mobile/android/base/strings.xml.in
+++ b/mobile/android/base/strings.xml.in
@@ -223,18 +223,16 @@
   <string name="pref_tracking_protection_enabled_pb">&pref_tracking_protection_enabled_pb;</string>
   <string name="pref_tracking_protection_disabled">&pref_tracking_protection_disabled;</string>
 
   <string name="pref_whats_new_notification">&pref_whats_new_notification;</string>
   <string name="pref_whats_new_notification_summary">&pref_whats_new_notification_summary;</string>
 
   <string name="pref_category_experimental">&pref_category_experimental;</string>
 
-  <string name="pref_custom_tabs">&pref_custom_tabs;</string>
-  <string name="pref_custom_tabs_summary">&pref_custom_tabs_summary3;</string>
   <string name="custom_tabs_menu_item_open_in">&custom_tabs_menu_item_open_in;</string>
   <string name="custom_tabs_menu_footer">&custom_tabs_menu_footer;</string>
   <string name="custom_tabs_hint_url_copy">&custom_tabs_hint_url_copy;</string>
 
   <string name="pref_pwa">&pref_pwa;</string>
   <string name="pref_pwa_summary">&pref_pwa_summary;</string>
 
   <string name="pref_char_encoding">&pref_char_encoding;</string>

--- a/mobile/android/moz.configure
+++ b/mobile/android/moz.configure
@@ -66,20 +66,16 @@ project_flag('MOZ_ANDROID_SEARCH_ACTIVIT
 project_flag('MOZ_ANDROID_MLS_STUMBLER',
              help='Include Mozilla Location Service Stumbler on Android',
              default=True)
 
 project_flag('MOZ_ANDROID_DOWNLOAD_CONTENT_SERVICE',
              help='Background service for downloading additional content at runtime',
              default=True)
 
-project_flag('MOZ_ANDROID_CUSTOM_TABS',
-             help='Enable support for Android custom tabs',
-             default=milestone.is_nightly)
-
 project_flag('MOZ_ANDROID_PWA',
              help='Enable support for Progressive Web Apps',
              default=milestone.is_nightly)
 
 # Enable the Switchboard A/B framework code.
 # Note: The framework is always included in the app. This flag controls
 # usage of the framework.
 project_flag('MOZ_SWITCHBOARD',