diff --git a/src/pages/login/login-page.tsx b/src/pages/login/login-page.tsx
index 89063ac..b0eb274 100644
--- a/src/pages/login/login-page.tsx
+++ b/src/pages/login/login-page.tsx
@@ -15,6 +15,21 @@ type SocialProvider =
   | 'kakao'
   | 'naver';
 
+const waitForMinimumLoadingTime = async (
+  startTime: number,
+  minimumTime = 3000,
+) => {
+  const elapsedTime = Date.now() - startTime;
+  const remainingTime = Math.max(
+    minimumTime - elapsedTime,
+    0,
+  );
+
+  await new Promise((resolve) =>
+    setTimeout(resolve, remainingTime),
+  );
+};
+
 interface SocialLoginResult {
   userId?: number;
   isNewUser: boolean;
@@ -44,6 +59,9 @@ const LoginPage = () => {
     setError('');
     setIsLoading(true);
 
+    const startTime = Date.now();
+
+
     try {
       const response = await api.post(
         `/api/auth/login/${provider}`,
@@ -63,6 +81,7 @@ const LoginPage = () => {
           setError(
             '소셜 회원가입 정보를 불러오지 못했습니다.',
           );
+          setIsLoading(false);
           return;
         }
 
@@ -82,19 +101,21 @@ const LoginPage = () => {
         setError(
           '로그인 토큰을 발급받지 못했습니다.',
         );
+        setIsLoading(false);
         return;
       }
 
       setAccessToken(result.accessToken);
 
+      await waitForMinimumLoadingTime(startTime);
+
       navigate('/');
     } catch {
-      setError(
-        '소셜 로그인에 실패했습니다.',
-      );
-    } finally {
-      setIsLoading(false);
-    }
+  setError(
+    '소셜 로그인에 실패했습니다.',
+  );
+  setIsLoading(false);
+}
   },
   [navigate],
 );
@@ -320,6 +341,8 @@ const handleNaverLogin = () => {
     setError('');
     setIsLoading(true);
 
+    const startTime = Date.now();
+
     try {
       const response = await api.post('/api/auth/login', {
         loginId: id.trim(),
@@ -330,12 +353,15 @@ const handleNaverLogin = () => {
 
       setAccessToken(accessToken);
 
+      await waitForMinimumLoadingTime(startTime);
+
       navigate('/');
     } catch {
-      setError('아이디 혹은 비밀번호가 일치하지 않습니다');
-    } finally {
-      setIsLoading(false);
-    }
+  setError(
+    '아이디 혹은 비밀번호가 일치하지 않습니다',
+  );
+  setIsLoading(false);
+}
   };
 
   if (isLoading) {
diff --git a/src/pages/signup/complete-page.tsx b/src/pages/signup/complete-page.tsx
index c95c3f7..61b5665 100644
--- a/src/pages/signup/complete-page.tsx
+++ b/src/pages/signup/complete-page.tsx
@@ -1,11 +1,12 @@
-import { useEffect } from 'react';
+import { useEffect,useState, } from 'react';
 import { useNavigate } from 'react-router-dom';
 import { getAccessToken } from '../../apis/token';
-
+import LoadingSpinner from '../../components/common/LoadingSpinner';
 import CompleteCheckIcon from '../../assets/icons/signup-complete.svg?react';
 
 const SignupCompletePage = () => {
   const navigate = useNavigate();
+  const [isLoading, setIsLoading] =useState(false);
 
   useEffect(() => {
     const accessToken = getAccessToken();
@@ -24,12 +25,26 @@ const SignupCompletePage = () => {
   }, [navigate]);
 
   const handleStart = () => {
-    sessionStorage.removeItem('signupProfileCompleted');
-    sessionStorage.removeItem('signupAgreedTermsIds');
+    setIsLoading(true);
+
+    sessionStorage.removeItem('signupProfileCompleted',);
+    sessionStorage.removeItem('signupAgreedTermsIds',);
 
-    navigate('/', { replace: true });
+    setTimeout(() => {
+      navigate('/', {
+        replace: true,
+      });
+    }, 3000);
   };
 
+  if (isLoading) {
+  return (
+    <div className='flex min-h-dvh items-center justify-center bg-white'>
+      <LoadingSpinner />
+    </div>
+  );
+}
+
   return (
     <div className='mx-auto flex h-dvh w-full max-w-[402px] flex-col overflow-hidden bg-white px-5 pb-[24px] font-pretendard text-text'>
       <main className='flex flex-1 flex-col items-center justify-center'>
diff --git a/src/pages/signup/signup-page.tsx b/src/pages/signup/signup-page.tsx
index fa487ac..2ca7d5d 100644
--- a/src/pages/signup/signup-page.tsx
+++ b/src/pages/signup/signup-page.tsx
@@ -117,7 +117,27 @@ const SignupPage = () => {
     setVerificationCode('');
 
     alert('인증번호를 발송했습니다.');
-  } catch {
+  } catch (error) {
+    if (!axios.isAxiosError(error) || !error.response) {
+      alert('인증번호 발송에 실패했습니다.');
+      return;
+    }
+
+    const {code,message,} = error.response.data;
+
+    // 이메일 형식이 올바르지 않은 경우
+    if (code === 'COMMON_400_002') {
+      alert('올바른 형식의 이메일 주소가 아닙니다.');
+      return;
+    }
+
+    // 이미 가입된 이메일인 경우
+    if (code === 'AUTH_409_001') {
+      alert(message);
+      return;
+    }
+
+    // 그 외 오류
     alert('인증번호 발송에 실패했습니다.');
   }
 };