diff --git a/lib/actions/user-actions.js b/lib/actions/user-actions.js
--- a/lib/actions/user-actions.js
+++ b/lib/actions/user-actions.js
@@ -457,6 +457,7 @@
 function useIdentityPasswordRegister(): (
   username: string,
   password: string,
+  fid: ?string,
 ) => Promise<IdentityAuthResult> {
   const client = React.useContext(IdentityClientContext);
   const identityClient = client?.identityClient;
@@ -470,6 +471,7 @@
   walletAddress: string,
   siweMessage: string,
   siweSignature: string,
+  fid: ?string,
 ) => Promise<IdentityAuthResult> {
   const client = React.useContext(IdentityClientContext);
   const identityClient = client?.identityClient;
diff --git a/lib/types/siwe-types.js b/lib/types/siwe-types.js
--- a/lib/types/siwe-types.js
+++ b/lib/types/siwe-types.js
@@ -129,3 +129,10 @@
   +message: string,
   +signature: string,
 };
+
+export type IdentityWalletRegisterInput = {
+  +address: string,
+  +message: string,
+  +signature: string,
+  +fid?: ?string,
+};
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
@@ -80,12 +80,16 @@
   const { setFID } = fidContext;
 
   const identityRegisterUsernameAccount = React.useCallback(
-    async (accountSelection: UsernameAccountSelection) => {
+    async (
+      accountSelection: UsernameAccountSelection,
+      farcasterID: ?string,
+    ) => {
       const identityRegisterPromise = (async () => {
         try {
           const result = await callIdentityPasswordRegister(
             accountSelection.username,
             accountSelection.password,
+            farcasterID,
           );
           await setNativeCredentials({
             username: accountSelection.username,
@@ -208,7 +212,10 @@
                 keyserverURL,
               );
             } else if (accountSelection.accountType === 'username') {
-              await identityRegisterUsernameAccount(accountSelection);
+              await identityRegisterUsernameAccount(
+                accountSelection,
+                farcasterID,
+              );
             } else if (!usingCommServicesAccessToken) {
               try {
                 await legacySiweServerCall(accountSelection, {
@@ -227,6 +234,7 @@
                   address: accountSelection.address,
                   message: accountSelection.message,
                   signature: accountSelection.signature,
+                  fid: farcasterID,
                 });
               } catch (e) {
                 Alert.alert(
diff --git a/native/account/siwe-hooks.js b/native/account/siwe-hooks.js
--- a/native/account/siwe-hooks.js
+++ b/native/account/siwe-hooks.js
@@ -14,7 +14,10 @@
   LogInStartingPayload,
   LogInExtraInfo,
 } from 'lib/types/account-types.js';
-import type { SIWEResult } from 'lib/types/siwe-types.js';
+import type {
+  SIWEResult,
+  IdentityWalletRegisterInput,
+} from 'lib/types/siwe-types.js';
 import { useLegacyAshoatKeyserverCall } from 'lib/utils/action-utils.js';
 import type { CallSingleKeyserverEndpointOptions } from 'lib/utils/call-single-keyserver-endpoint.js';
 import { useDispatchActionPromise } from 'lib/utils/redux-promise-utils.js';
@@ -113,12 +116,17 @@
   );
 }
 
-function useIdentityWalletRegisterCall(): SIWEResult => Promise<void> {
+function useIdentityWalletRegisterCall(): IdentityWalletRegisterInput => Promise<void> {
   const identityWalletRegister = useIdentityWalletRegister();
   const dispatchActionPromise = useDispatchActionPromise();
   return React.useCallback(
-    async ({ address, message, signature }) => {
-      const siwePromise = identityWalletRegister(address, message, signature);
+    async ({ address, message, signature, fid }) => {
+      const siwePromise = identityWalletRegister(
+        address,
+        message,
+        signature,
+        fid,
+      );
       void dispatchActionPromise(identityRegisterActionTypes, siwePromise);
 
       await siwePromise;
diff --git a/native/identity-service/identity-service-context-provider.react.js b/native/identity-service/identity-service-context-provider.react.js
--- a/native/identity-service/identity-service-context-provider.react.js
+++ b/native/identity-service/identity-service-context-provider.react.js
@@ -296,7 +296,11 @@
           oneTimeKeys.notificationsOneTimeKeys,
         );
       },
-      registerPasswordUser: async (username: string, password: string) => {
+      registerPasswordUser: async (
+        username: string,
+        password: string,
+        fid: ?string,
+      ) => {
         await commCoreModule.initializeCryptoAccount();
         const [
           { blobPayload, signature, primaryIdentityPublicKeys },
@@ -318,7 +322,7 @@
           prekeys.notifPrekeySignature,
           getOneTimeKeyValues(contentOneTimeKeys),
           getOneTimeKeyValues(notificationsOneTimeKeys),
-          '',
+          fid ?? '',
         );
         const { userID, accessToken: token } = JSON.parse(registrationResult);
         const identityAuthResult = { accessToken: token, userID, username };
@@ -373,6 +377,7 @@
         walletAddress: string,
         siweMessage: string,
         siweSignature: string,
+        fid: ?string,
       ) => {
         await commCoreModule.initializeCryptoAccount();
         const [
@@ -395,7 +400,7 @@
           prekeys.notifPrekeySignature,
           getOneTimeKeyValues(contentOneTimeKeys),
           getOneTimeKeyValues(notificationsOneTimeKeys),
-          '',
+          fid ?? '',
         );
         const { userID, accessToken: token } = JSON.parse(registrationResult);
         const identityAuthResult = {