diff --git a/lib/types/identity-service-types.js b/lib/types/identity-service-types.js
--- a/lib/types/identity-service-types.js
+++ b/lib/types/identity-service-types.js
@@ -62,3 +62,5 @@
   +username?: ?string,
   +walletAddress?: ?string,
 };
+
+export const ONE_TIME_KEYS_NUMBER: number = Object.freeze(10);
diff --git a/lib/types/redux-types.js b/lib/types/redux-types.js
--- a/lib/types/redux-types.js
+++ b/lib/types/redux-types.js
@@ -42,6 +42,7 @@
   CalendarThreadFilter,
   SetCalendarDeletedFilterPayload,
 } from './filter-types.js';
+import type { UserLoginResponse } from './identity-service-types.js';
 import type { IntegrityStore } from './integrity-types.js';
 import type {
   KeyserverStore,
@@ -340,6 +341,21 @@
       +payload: RegisterResult,
       +loadingInfo: LoadingInfo,
     }
+  | {
+      +type: 'IDENTITY_REGISTER_STARTED',
+      +payload?: void,
+      +loadingInfo: LoadingInfo,
+    }
+  | {
+      +type: 'IDENTITY_REGISTER_FAILED',
+      +payload: Error,
+      +loadingInfo: LoadingInfo,
+    }
+  | {
+      +type: 'IDENTITY_REGISTER_SUCCESS',
+      +payload: UserLoginResponse,
+      +loadingInfo: LoadingInfo,
+    }
   | {
       +type: 'CHANGE_USER_PASSWORD_STARTED',
       +payload?: void,
diff --git a/native/account/registration/registration-server-call.js b/native/account/registration/registration-server-call.js
--- a/native/account/registration/registration-server-call.js
+++ b/native/account/registration/registration-server-call.js
@@ -6,13 +6,18 @@
 import {
   keyserverRegisterActionTypes,
   keyserverRegister,
+  useIdentityRegister,
+  identityRegisterActionTypes,
 } from 'lib/actions/user-actions.js';
+import { getOneTimeKeyArray } from 'lib/shared/crypto-utils.js';
 import type { LogInStartingPayload } from 'lib/types/account-types.js';
+import { ONE_TIME_KEYS_NUMBER } from 'lib/types/identity-service-types.js';
 import {
   useServerCall,
   useDispatchActionPromise,
 } from 'lib/utils/action-utils.js';
 import { useDispatch } from 'lib/utils/redux-utils.js';
+import { usingCommServicesAccessToken } from 'lib/utils/services-utils.js';
 import { setURLPrefix } from 'lib/utils/url-utils.js';
 
 import type {
@@ -24,6 +29,7 @@
   useNativeSetUserAvatar,
   useUploadSelectedMedia,
 } from '../../avatars/avatar-hooks.js';
+import { commRustModule, commCoreModule } from '../../native-modules.js';
 import { NavContext } from '../../navigation/navigation-context.js';
 import { useSelector } from '../../redux/redux-utils.js';
 import { nativeLogInExtraInfoSelector } from '../../selectors/account-selectors.js';
@@ -68,17 +74,90 @@
   );
 
   const dispatchActionPromise = useDispatchActionPromise();
-  const callRegister = useServerCall(keyserverRegister);
+  const callKeyserverRegister = useServerCall(keyserverRegister);
+  const callIdentityRegister = useIdentityRegister;
 
-  const registerUsernameAccount = React.useCallback(
+  const identityRegisterUsernameAccount = React.useCallback(
+    async (accountSelection: UsernameAccountSelection) => {
+      const [
+        {
+          notificationIdentityPublicKeys,
+          primaryIdentityPublicKeys,
+          signature,
+        },
+        notificationsOneTimeKeys,
+        primaryOneTimeKeys,
+        prekeys,
+      ] = await Promise.all([
+        commCoreModule.getUserPublicKey(),
+        commCoreModule.getNotificationsOneTimeKeys(ONE_TIME_KEYS_NUMBER),
+        commCoreModule.getPrimaryOneTimeKeys(ONE_TIME_KEYS_NUMBER),
+        commCoreModule.generateAndGetPrekeys(),
+      ]);
+      const keyPayload = JSON.stringify({
+        notificationIdentityPublicKeys,
+        primaryIdentityPublicKeys,
+      });
+      const identityRegisterPromise = (async () => {
+        try {
+          await callIdentityRegister(
+            commRustModule,
+            accountSelection.username,
+            accountSelection.password,
+            keyPayload,
+            signature,
+            prekeys.contentPrekey,
+            prekeys.contentPrekeySignature,
+            prekeys.notifPrekey,
+            prekeys.notifPrekeySignature,
+            getOneTimeKeyArray(primaryOneTimeKeys),
+            getOneTimeKeyArray(notificationsOneTimeKeys),
+          );
+          await setNativeCredentials({
+            username: accountSelection.username,
+            password: accountSelection.password,
+          });
+        } catch (e) {
+          if (e.message === 'username reserved') {
+            Alert.alert(
+              'Username reserved',
+              'This username is currently reserved. Please contact support@' +
+                'comm.app if you would like to claim this account.',
+            );
+          } else if (e.message === 'username already exists') {
+            Alert.alert(
+              'Username taken',
+              'An account with that username already exists',
+            );
+          } else if (e.message === 'Unsupported version') {
+            Alert.alert(
+              AppOutOfDateAlertDetails.title,
+              AppOutOfDateAlertDetails.message,
+            );
+          } else {
+            Alert.alert('Unknown error', 'Uhh... try again?');
+          }
+          throw e;
+        }
+      })();
+      void dispatchActionPromise(
+        identityRegisterActionTypes,
+        identityRegisterPromise,
+      );
+      await identityRegisterPromise;
+    },
+    [callIdentityRegister, dispatchActionPromise],
+  );
+
+  const keyserverRegisterUsernameAccount = React.useCallback(
     async (
       accountSelection: UsernameAccountSelection,
       keyserverURL: string,
     ) => {
       const extraInfo = await logInExtraInfo();
-      const registerPromise = (async () => {
+      const keyserverRegisterPromise = (async () => {
         try {
-          const result = await callRegister(
+          const result = await callKeyserverRegister(
             {
               ...extraInfo,
               username: accountSelection.username,
@@ -118,13 +197,13 @@
       })();
       void dispatchActionPromise(
         keyserverRegisterActionTypes,
-        registerPromise,
+        keyserverRegisterPromise,
         undefined,
         ({ calendarQuery: extraInfo.calendarQuery }: LogInStartingPayload),
       );
-      await registerPromise;
+      await keyserverRegisterPromise;
     },
-    [logInExtraInfo, callRegister, dispatchActionPromise],
+    [logInExtraInfo, callKeyserverRegister, dispatchActionPromise],
   );
 
   const siweServerCall = useSIWEServerCall();
@@ -139,8 +218,16 @@
               return;
             }
             const { accountSelection, avatarData, keyserverURL } = input;
-            if (accountSelection.accountType === 'username') {
-              await registerUsernameAccount(accountSelection, keyserverURL);
+            if (
+              accountSelection.accountType === 'username' &&
+              !usingCommServicesAccessToken
+            ) {
+              await keyserverRegisterUsernameAccount(
+                accountSelection,
+                keyserverURL,
+              );
+            } else if (accountSelection.accountType === 'username') {
+              await identityRegisterUsernameAccount(accountSelection);
             } else {
               try {
                 await siweServerCall(accountSelection, {
@@ -166,7 +253,13 @@
           }
         },
       ),
-    [currentStep, registerUsernameAccount, siweServerCall, dispatch],
+    [
+      currentStep,
+      keyserverRegisterUsernameAccount,
+      identityRegisterUsernameAccount,
+      siweServerCall,
+      dispatch,
+    ],
   );
 
   // STEP 2: SETTING AVATAR