diff --git a/frontend/lib/features/admin/presentation/create_user_screen.dart b/frontend/lib/features/admin/presentation/create_user_screen.dart
index da5337ea..69418cfc 100644
--- a/frontend/lib/features/admin/presentation/create_user_screen.dart
+++ b/frontend/lib/features/admin/presentation/create_user_screen.dart
@@ -108,12 +108,28 @@ class _CreateUserScreenState extends State<CreateUserScreen> {
 
     setState(() => _isLoading = true);
 
+    String loginId = _loginIdController.text.trim();
+    if (!loginId.contains('@')) {
+      loginId = loginId.replaceAll(RegExp(r'[-\s]'), '');
+      if (loginId.startsWith('010')) {
+        loginId = '+82${loginId.substring(1)}';
+      }
+    }
+
+    String? phone = _phoneController.text.trim().isEmpty ? null : _phoneController.text.trim();
+    if (phone != null && !phone.contains('@')) {
+      phone = phone.replaceAll(RegExp(r'[-\s]'), '');
+      if (phone.startsWith('010')) {
+        phone = '+82${phone.substring(1)}';
+      }
+    }
+
     try {
       await AuthProxyService.createUser(
-        loginId: _loginIdController.text.trim(),
+        loginId: loginId,
         adminPassword: _verifiedAdminPassword!,
         email: _emailController.text.trim().isEmpty ? null : _emailController.text.trim(),
-        phone: _phoneController.text.trim().isEmpty ? null : _phoneController.text.trim(),
+        phone: phone,
         displayName: _nameController.text.trim().isEmpty ? null : _nameController.text.trim(),
       );
 
diff --git a/frontend/lib/features/admin/presentation/user_management_screen.dart b/frontend/lib/features/admin/presentation/user_management_screen.dart
index f779e779..f61f94fb 100644
--- a/frontend/lib/features/admin/presentation/user_management_screen.dart
+++ b/frontend/lib/features/admin/presentation/user_management_screen.dart
@@ -205,13 +205,22 @@ class _UserManagementScreenState extends State<UserManagementScreen> with Single
     if (confirm != true) return;
 
     setState(() => _isLoading = true);
+
+    String? phone = phoneController.text.trim().isEmpty ? null : phoneController.text.trim();
+    if (phone != null && !phone.contains('@')) {
+      phone = phone.replaceAll(RegExp(r'[-\s]'), '');
+      if (phone.startsWith('010')) {
+        phone = '+82${phone.substring(1)}';
+      }
+    }
+
     try {
       await AuthProxyService.updateUserDetails(
         adminPassword: _verifiedAdminPassword!,
         loginId: loginId,
         displayName: nameController.text.trim(),
         email: emailController.text.trim(),
-        phone: phoneController.text.trim(),
+        phone: phone,
       );
       _showSuccess("User updated successfully");
       _loadUsers(query: _searchController.text);
@@ -228,12 +237,29 @@ class _UserManagementScreenState extends State<UserManagementScreen> with Single
     if (_verifiedAdminPassword == null) return;
 
     setState(() => _isLoading = true);
+
+    String loginId = _createLoginIdController.text.trim();
+    if (!loginId.contains('@')) {
+      loginId = loginId.replaceAll(RegExp(r'[-\s]'), '');
+      if (loginId.startsWith('010')) {
+        loginId = '+82${loginId.substring(1)}';
+      }
+    }
+
+    String? phone = _createPhoneController.text.trim().isEmpty ? null : _createPhoneController.text.trim();
+    if (phone != null && !phone.contains('@')) {
+      phone = phone.replaceAll(RegExp(r'[-\s]'), '');
+      if (phone.startsWith('010')) {
+        phone = '+82${phone.substring(1)}';
+      }
+    }
+
     try {
       await AuthProxyService.createUser(
-        loginId: _createLoginIdController.text.trim(),
+        loginId: loginId,
         adminPassword: _verifiedAdminPassword!,
         email: _createEmailController.text.trim().isEmpty ? null : _createEmailController.text.trim(),
-        phone: _createPhoneController.text.trim().isEmpty ? null : _createPhoneController.text.trim(),
+        phone: phone,
         displayName: _createNameController.text.trim().isEmpty ? null : _createNameController.text.trim(),
       );
 
diff --git a/frontend/lib/features/auth/presentation/forgot_password_screen.dart b/frontend/lib/features/auth/presentation/forgot_password_screen.dart
index 0b80e708..ae2b82e7 100644
--- a/frontend/lib/features/auth/presentation/forgot_password_screen.dart
+++ b/frontend/lib/features/auth/presentation/forgot_password_screen.dart
@@ -14,15 +14,25 @@ class _ForgotPasswordScreenState extends State<ForgotPasswordScreen> {
   bool _isLoading = false;
 
   Future<void> _handlePasswordReset() async {
-    if (_loginIdController.text.trim().isEmpty) {
+    final input = _loginIdController.text.trim();
+    if (input.isEmpty) {
       _showError("이메일 또는 휴대폰 번호를 입력해주세요.");
       return;
     }
 
+    String loginId = input;
+    if (!input.contains('@')) {
+      // Format phone number if it's not an email
+      loginId = input.replaceAll(RegExp(r'[-\s]'), '');
+      if (loginId.startsWith('010')) {
+        loginId = '+82${loginId.substring(1)}';
+      }
+    }
+
     setState(() => _isLoading = true);
 
     try {
-      await AuthProxyService.initiatePasswordReset(_loginIdController.text.trim());
+      await AuthProxyService.initiatePasswordReset(loginId);
       if (mounted) {
         ScaffoldMessenger.of(context).showSnackBar(
           const SnackBar(
diff --git a/frontend/lib/features/auth/presentation/login_screen.dart b/frontend/lib/features/auth/presentation/login_screen.dart
index 78390bbe..e2fefbf0 100644
--- a/frontend/lib/features/auth/presentation/login_screen.dart
+++ b/frontend/lib/features/auth/presentation/login_screen.dart
@@ -245,13 +245,22 @@ class _LoginScreenState extends ConsumerState<LoginScreen>
 
   // 이메일/비밀번호 로그인 처리
   Future<void> _handlePasswordLogin() async {
-    final loginId = _passwordLoginIdController.text.trim();
+    final input = _passwordLoginIdController.text.trim();
     final password = _passwordController.text.trim();
-    if (loginId.isEmpty || password.isEmpty) {
+    if (input.isEmpty || password.isEmpty) {
       _showError("이메일(또는 전화번호)와 비밀번호를 모두 입력해주세요.");
       return;
     }
 
+    String loginId = input;
+    if (!input.contains('@')) {
+      // Format phone number if it's not an email
+      loginId = input.replaceAll(RegExp(r'[-\s]'), '');
+      if (loginId.startsWith('010')) {
+        loginId = '+82${loginId.substring(1)}';
+      }
+    }
+
     // 로딩 인디케이터 표시
     showDialog(
       context: context,