diff --git a/src/encryptid/index.ts b/src/encryptid/index.ts
index 7992dee..923760c 100644
--- a/src/encryptid/index.ts
+++ b/src/encryptid/index.ts
@@ -78,6 +78,15 @@ export {
   type AccountVault,
 } from './vault';
 
+// ============================================================================
+// WALLET SYNC
+// ============================================================================
+
+export {
+  syncWalletsOnLogin,
+  syncWalletsToVault,
+} from './wallet-sync';
+
 // ============================================================================
 // UI COMPONENTS
 // ============================================================================
diff --git a/src/encryptid/ui/login-button.ts b/src/encryptid/ui/login-button.ts
index 36e7975..3dd3ce7 100644
--- a/src/encryptid/ui/login-button.ts
+++ b/src/encryptid/ui/login-button.ts
@@ -16,6 +16,7 @@ import { getKeyManager } from '../key-derivation';
 import { getSessionManager, AuthLevel } from '../session';
 import { getDocBridge, resetDocBridge } from '../../../shared/local-first/encryptid-bridge';
 import { getVaultManager, resetVaultManager } from '../vault';
+import { syncWalletsOnLogin } from '../wallet-sync';
 
 // ============================================================================
 // STYLES
@@ -415,9 +416,9 @@ export class EncryptIDLoginButton extends HTMLElement {
         // Load encrypted account vault in background
         const docCrypto = getDocBridge().getDocCrypto();
         if (docCrypto) {
-          getVaultManager(docCrypto).load().catch(err =>
-            console.warn('Vault load failed:', err)
-          );
+          getVaultManager(docCrypto).load()
+            .then(() => syncWalletsOnLogin(docCrypto))
+            .catch(err => console.warn('Vault load failed:', err));
         }
       }
 
@@ -429,7 +430,7 @@ export class EncryptIDLoginButton extends HTMLElement {
       await sessionManager.createSession(result, keys.did, {
         encrypt: true,
         sign: true,
-        wallet: false,  // Will be true after wallet setup
+        wallet: !!keys.eoaAddress,
       });
 
       // Dispatch success event
@@ -534,9 +535,9 @@ export class EncryptIDLoginButton extends HTMLElement {
           // Load encrypted account vault in background
           const docCrypto = getDocBridge().getDocCrypto();
           if (docCrypto) {
-            getVaultManager(docCrypto).load().catch(err =>
-              console.warn('Vault load failed:', err)
-            );
+            getVaultManager(docCrypto).load()
+              .then(() => syncWalletsOnLogin(docCrypto))
+              .catch(err => console.warn('Vault load failed:', err));
           }
         }
 
@@ -546,7 +547,7 @@ export class EncryptIDLoginButton extends HTMLElement {
         await sessionManager.createSession(result, keys.did, {
           encrypt: true,
           sign: true,
-          wallet: false,
+          wallet: !!keys.eoaAddress,
         });
 
         this.dispatchEvent(new CustomEvent('login-success', {
diff --git a/src/encryptid/wallet-sync.ts b/src/encryptid/wallet-sync.ts
new file mode 100644
index 0000000..d5a8fe4
--- /dev/null
+++ b/src/encryptid/wallet-sync.ts
@@ -0,0 +1,145 @@
+/**
+ * EncryptID Wallet Sync
+ *
+ * Bridges WalletStore (encrypted localStorage) ↔ VaultManager (encrypted server blob)
+ * so wallet associations survive across devices.
+ *
+ * On login:
+ *   1. Load vault from server
+ *   2. Merge vault wallets into local WalletStore (new entries only)
+ *   3. Merge local wallets into vault (in case this device has wallets the vault doesn't)
+ *   4. Save vault if anything changed
+ *
+ * On wallet add/remove:
+ *   syncWalletsToVault() pushes current WalletStore state into the vault.
+ */
+
+import { getWalletStore, type SafeWalletEntry } from './wallet-store';
+import { getVaultManager, type AccountVault } from './vault';
+import { getKeyManager } from './key-derivation';
+import type { DocCrypto } from '../../shared/local-first/crypto';
+
+/**
+ * After login + vault load, merge wallets bidirectionally between
+ * the local WalletStore and the remote AccountVault.
+ *
+ * Requires PRF-derived encryption key (for WalletStore) and DocCrypto (for VaultManager).
+ */
+export async function syncWalletsOnLogin(docCrypto: DocCrypto): Promise<void> {
+  try {
+    const km = getKeyManager();
+    if (!km.isInitialized()) return;
+
+    const keys = await km.getKeys();
+    if (!keys.encryptionKey) return;
+
+    const walletStore = getWalletStore(keys.encryptionKey);
+    const vaultManager = getVaultManager(docCrypto);
+
+    const vault = await vaultManager.get();
+    const localWallets = await walletStore.list();
+    const vaultWallets = vault.wallets || [];
+
+    let changed = false;
+
+    // 1. Restore vault wallets → local WalletStore (if not already present)
+    for (const vw of vaultWallets) {
+      const exists = localWallets.find(
+        lw => lw.safeAddress.toLowerCase() === vw.safeAddress.toLowerCase()
+          && lw.chainId === vw.chainId
+      );
+      if (!exists) {
+        await walletStore.add({
+          safeAddress: vw.safeAddress,
+          chainId: vw.chainId,
+          eoaAddress: vw.eoaAddress,
+          label: vw.label,
+        });
+      }
+    }
+
+    // 2. Push local wallets → vault (if not already present)
+    const updatedLocal = await walletStore.list();
+    const updatedVaultWallets = [...vaultWallets];
+
+    for (const lw of updatedLocal) {
+      const exists = updatedVaultWallets.find(
+        vw => vw.safeAddress.toLowerCase() === lw.safeAddress.toLowerCase()
+          && vw.chainId === lw.chainId
+      );
+      if (!exists) {
+        updatedVaultWallets.push({
+          id: lw.id,
+          safeAddress: lw.safeAddress,
+          chainId: lw.chainId,
+          eoaAddress: lw.eoaAddress,
+          label: lw.label,
+          addedAt: lw.addedAt,
+        });
+        changed = true;
+      }
+    }
+
+    // 3. Also ensure the server-side wallet_address profile field is set
+    //    This is the fallback for mobile (no PRF) — the JWT carries it.
+    if (keys.eoaAddress) {
+      await setServerWalletAddress(keys.eoaAddress).catch(() => {});
+    }
+
+    // 4. Save vault if anything changed
+    if (changed) {
+      await vaultManager.update({ wallets: updatedVaultWallets });
+    }
+  } catch (err) {
+    console.warn('Wallet sync failed:', err);
+  }
+}
+
+/**
+ * Push current WalletStore state into the vault.
+ * Call this after any wallet add/update/remove operation.
+ */
+export async function syncWalletsToVault(docCrypto: DocCrypto): Promise<void> {
+  try {
+    const km = getKeyManager();
+    if (!km.isInitialized()) return;
+
+    const keys = await km.getKeys();
+    if (!keys.encryptionKey) return;
+
+    const walletStore = getWalletStore(keys.encryptionKey);
+    const vaultManager = getVaultManager(docCrypto);
+
+    const localWallets = await walletStore.list();
+    const vaultWallets = localWallets.map(lw => ({
+      id: lw.id,
+      safeAddress: lw.safeAddress,
+      chainId: lw.chainId,
+      eoaAddress: lw.eoaAddress,
+      label: lw.label,
+      addedAt: lw.addedAt,
+    }));
+
+    await vaultManager.update({ wallets: vaultWallets });
+  } catch (err) {
+    console.warn('Wallet vault sync failed:', err);
+  }
+}
+
+/**
+ * Set the wallet address on the server user profile.
+ * This ensures the JWT carries the wallet address for non-PRF devices (mobile).
+ */
+async function setServerWalletAddress(walletAddress: string): Promise<void> {
+  const token = localStorage.getItem('encryptid_token');
+  if (!token) return;
+
+  await fetch('/encryptid/api/wallet-capability', {
+    method: 'POST',
+    headers: {
+      'Authorization': `Bearer ${token}`,
+      'Content-Type': 'application/json',
+    },
+    body: JSON.stringify({ walletAddress }),
+  });
+}