diff --git a/Tethering/src/com/android/networkstack/tethering/PrivateAddressCoordinator.java b/Tethering/src/com/android/networkstack/tethering/PrivateAddressCoordinator.java
index c1e7127..cc2422f 100644
--- a/Tethering/src/com/android/networkstack/tethering/PrivateAddressCoordinator.java
+++ b/Tethering/src/com/android/networkstack/tethering/PrivateAddressCoordinator.java
@@ -90,11 +90,8 @@
         mCachedAddresses.put(TETHERING_BLUETOOTH, new LinkAddress(LEGACY_BLUETOOTH_IFACE_ADDRESS));
         mCachedAddresses.put(TETHERING_WIFI_P2P, new LinkAddress(LEGACY_WIFI_P2P_IFACE_ADDRESS));
 
-        mTetheringPrefixes = new ArrayList<>(Arrays.asList(new IpPrefix("192.168.0.0/16")));
-        if (config.isSelectAllPrefixRangeEnabled()) {
-            mTetheringPrefixes.add(new IpPrefix("172.16.0.0/12"));
-            mTetheringPrefixes.add(new IpPrefix("10.0.0.0/8"));
-        }
+        mTetheringPrefixes = new ArrayList<>(Arrays.asList(new IpPrefix("192.168.0.0/16"),
+            new IpPrefix("172.16.0.0/12"), new IpPrefix("10.0.0.0/8")));
     }
 
     /**
diff --git a/Tethering/src/com/android/networkstack/tethering/TetheringConfiguration.java b/Tethering/src/com/android/networkstack/tethering/TetheringConfiguration.java
index dd0d567..8488a9a 100644
--- a/Tethering/src/com/android/networkstack/tethering/TetheringConfiguration.java
+++ b/Tethering/src/com/android/networkstack/tethering/TetheringConfiguration.java
@@ -99,13 +99,6 @@
             "use_legacy_wifi_p2p_dedicated_ip";
 
     /**
-     * Flag use to enable select all prefix ranges feature.
-     * TODO: Remove this flag if there are no problems after M-2020-12 rolls out.
-     */
-    public static final String TETHER_ENABLE_SELECT_ALL_PREFIX_RANGES =
-            "tether_enable_select_all_prefix_ranges";
-
-    /**
      * Experiment flag to force choosing upstreams automatically.
      *
      * This setting is intended to help force-enable the feature on OEM devices that disabled it
@@ -157,7 +150,6 @@
     private final boolean mEnableBpfOffload;
     private final boolean mEnableWifiP2pDedicatedIp;
 
-    private final boolean mEnableSelectAllPrefixRange;
     private final int mUsbTetheringFunction;
     protected final ContentResolver mContentResolver;
 
@@ -222,11 +214,6 @@
                 R.bool.config_tether_enable_legacy_wifi_p2p_dedicated_ip,
                 false /* defaultValue */);
 
-        // Flags should normally not be booleans, but this is a kill-switch flag that is only used
-        // to turn off the feature, so binary rollback problems do not apply.
-        mEnableSelectAllPrefixRange = getDeviceConfigBoolean(
-                TETHER_ENABLE_SELECT_ALL_PREFIX_RANGES, true /* defaultValue */);
-
         configLog.log(toString());
     }
 
@@ -318,9 +305,6 @@
         pw.print("enableWifiP2pDedicatedIp: ");
         pw.println(mEnableWifiP2pDedicatedIp);
 
-        pw.print("mEnableSelectAllPrefixRange: ");
-        pw.println(mEnableSelectAllPrefixRange);
-
         pw.print("mUsbTetheringFunction: ");
         pw.println(isUsingNcm() ? "NCM" : "RNDIS");
     }
@@ -384,10 +368,6 @@
         return mEnableBpfOffload;
     }
 
-    public boolean isSelectAllPrefixRangeEnabled() {
-        return mEnableSelectAllPrefixRange;
-    }
-
     private int getUsbTetheringFunction(Resources res) {
         final int valueFromRes = getResourceInteger(res, R.integer.config_tether_usb_functions,
                 TETHER_USB_RNDIS_FUNCTION /* defaultValue */);
diff --git a/Tethering/tests/mts/src/android/tethering/mts/TetheringModuleTest.java b/Tethering/tests/mts/src/android/tethering/mts/TetheringModuleTest.java
index ef254ff..4525568 100644
--- a/Tethering/tests/mts/src/android/tethering/mts/TetheringModuleTest.java
+++ b/Tethering/tests/mts/src/android/tethering/mts/TetheringModuleTest.java
@@ -29,7 +29,6 @@
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.fail;
-import static org.junit.Assume.assumeTrue;
 
 import android.app.UiAutomation;
 import android.content.Context;
@@ -81,12 +80,8 @@
         mUiAutomation.dropShellPermissionIdentity();
     }
 
-    private static final String TETHER_ENABLE_SELECT_ALL_PREFIX_RANGES =
-            "tether_enable_select_all_prefix_ranges";
     @Test
     public void testSwitchBasePrefixRangeWhenConflict() throws Exception {
-        assumeTrue(isFeatureEnabled(TETHER_ENABLE_SELECT_ALL_PREFIX_RANGES, true));
-
         addressConflictTest(true);
     }
 
diff --git a/Tethering/tests/unit/src/com/android/networkstack/tethering/PrivateAddressCoordinatorTest.java b/Tethering/tests/unit/src/com/android/networkstack/tethering/PrivateAddressCoordinatorTest.java
index 6c98f2f..55d9852 100644
--- a/Tethering/tests/unit/src/com/android/networkstack/tethering/PrivateAddressCoordinatorTest.java
+++ b/Tethering/tests/unit/src/com/android/networkstack/tethering/PrivateAddressCoordinatorTest.java
@@ -100,7 +100,6 @@
         when(mContext.getSystemService(Context.CONNECTIVITY_SERVICE)).thenReturn(mConnectivityMgr);
         when(mConnectivityMgr.getAllNetworks()).thenReturn(mAllNetworks);
         when(mConfig.shouldEnableWifiP2pDedicatedIp()).thenReturn(false);
-        when(mConfig.isSelectAllPrefixRangeEnabled()).thenReturn(true);
         setUpIpServers();
         mPrivateAddressCoordinator = spy(new PrivateAddressCoordinator(mContext, mConfig));
     }
diff --git a/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringConfigurationTest.java b/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringConfigurationTest.java
index c0c2ab9..11e19eb 100644
--- a/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringConfigurationTest.java
+++ b/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringConfigurationTest.java
@@ -182,7 +182,6 @@
         when(mResources.getBoolean(R.bool.config_tether_enable_legacy_wifi_p2p_dedicated_ip))
                 .thenReturn(false);
         initializeBpfOffloadConfiguration(true, null /* unset */);
-        initEnableSelectAllPrefixRangeFlag(null /* unset */);
 
         mHasTelephonyManager = true;
         mMockContext = new MockContext(mContext);
@@ -490,32 +489,6 @@
         assertTrue(testCfg.shouldEnableWifiP2pDedicatedIp());
     }
 
-    private void initEnableSelectAllPrefixRangeFlag(final String value) {
-        doReturn(value).when(
-                () -> DeviceConfig.getProperty(eq(NAMESPACE_CONNECTIVITY),
-                eq(TetheringConfiguration.TETHER_ENABLE_SELECT_ALL_PREFIX_RANGES)));
-    }
-
-    @Test
-    public void testSelectAllPrefixRangeFlag() throws Exception {
-        // Test default value.
-        final TetheringConfiguration defaultCfg = new TetheringConfiguration(
-                mMockContext, mLog, INVALID_SUBSCRIPTION_ID);
-        assertTrue(defaultCfg.isSelectAllPrefixRangeEnabled());
-
-        // Test disable flag.
-        initEnableSelectAllPrefixRangeFlag("false");
-        final TetheringConfiguration testDisable = new TetheringConfiguration(
-                mMockContext, mLog, INVALID_SUBSCRIPTION_ID);
-        assertFalse(testDisable.isSelectAllPrefixRangeEnabled());
-
-        // Test enable flag.
-        initEnableSelectAllPrefixRangeFlag("true");
-        final TetheringConfiguration testEnable = new TetheringConfiguration(
-                mMockContext, mLog, INVALID_SUBSCRIPTION_ID);
-        assertTrue(testEnable.isSelectAllPrefixRangeEnabled());
-    }
-
     @Test
     public void testChooseUpstreamAutomatically() throws Exception {
         when(mResources.getBoolean(R.bool.config_tether_upstream_automatic))