diff --git a/src/app/(with-header)/myactivity/[id]/hooks/useEditActivityForm.ts b/src/app/(with-header)/myactivity/[id]/hooks/useEditActivityForm.ts
index 7ed9ba5f..6290a048 100644
--- a/src/app/(with-header)/myactivity/[id]/hooks/useEditActivityForm.ts
+++ b/src/app/(with-header)/myactivity/[id]/hooks/useEditActivityForm.ts
@@ -9,6 +9,7 @@ import { ActivityDetailEdit, Schedule } from '@/types/activityDetailType';
 import { AxiosError } from 'axios';
 import { toast } from 'sonner';
 import { notFound } from 'next/navigation';
+import { validateSchedules } from '../../utils/dateValidatoin';
 
 interface SubImageType {
   id?: number;
@@ -208,6 +209,11 @@ export const useEditActivityForm = () => {
 
   const handleSubmit = async (e: React.FormEvent) => {
     e.preventDefault();
+    const validationMessage = validateSchedules(dates);
+    if (validationMessage) {
+      toast.error(validationMessage);
+      return;
+    }
     try {
       await mutation.mutateAsync();
     } catch (error) {
diff --git a/src/app/(with-header)/myactivity/components/ScheduleSelect.tsx b/src/app/(with-header)/myactivity/components/ScheduleSelect.tsx
index c00f2cdd..c64fd3f5 100644
--- a/src/app/(with-header)/myactivity/components/ScheduleSelect.tsx
+++ b/src/app/(with-header)/myactivity/components/ScheduleSelect.tsx
@@ -19,7 +19,6 @@ interface ScheduleSelectProps {
 export function ScheduleSelect({
   index,
   isRemovable,
-
   onRemove,
   onDateChange,
   onStartTimeChange,
@@ -29,9 +28,9 @@ export function ScheduleSelect({
   endTime,
 }: ScheduleSelectProps) {
   return (
-    <div className='pt-5 w-full'>
-      <div className='flex flex-wrap items-end gap-4 w-full'>
-        <div className='flex flex-col gap-10 flex-1 min-w-0'>
+    <div className='w-full pt-5'>
+      <div className='flex w-full flex-wrap items-end gap-4'>
+        <div className='flex min-w-0 flex-1 flex-col gap-10'>
           <Input
             className='w-full'
             type='date'
@@ -40,7 +39,7 @@ export function ScheduleSelect({
             variant='compact'
           />
         </div>
-        <div className='flex flex-col gap-10 flex-1 min-w-0'>
+        <div className='flex min-w-0 flex-1 flex-col gap-10'>
           <Input
             className='w-full'
             type='time'
@@ -49,7 +48,7 @@ export function ScheduleSelect({
             variant='compact'
           />
         </div>
-        <div className='flex flex-col gap-10 flex-1 min-w-0'>
+        <div className='flex min-w-0 flex-1 flex-col gap-10'>
           <Input
             className='w-full'
             type='time'
@@ -61,11 +60,11 @@ export function ScheduleSelect({
 
         <div className='flex-shrink-0'>
           {isRemovable && (
-            <div className="flex-shrink-0 w-44">
+            <div className='w-44 flex-shrink-0'>
               <button
-                type="button"
+                type='button'
                 onClick={() => onRemove(index)}
-                className="w-full h-46 border border-gray-300 rounded-[10px] flex items-center justify-center hover:bg-gray-100"
+                className='flex h-46 w-full items-center justify-center rounded-[10px] border border-gray-300 hover:bg-gray-100'
               >
                 <IconClose />
               </button>
diff --git a/src/app/(with-header)/myactivity/components/ScheduleSelectForm.tsx b/src/app/(with-header)/myactivity/components/ScheduleSelectForm.tsx
index 8115b04e..4e63ec11 100644
--- a/src/app/(with-header)/myactivity/components/ScheduleSelectForm.tsx
+++ b/src/app/(with-header)/myactivity/components/ScheduleSelectForm.tsx
@@ -1,5 +1,6 @@
 'use client';
 
+import { toast } from 'sonner';
 import { ScheduleSelect } from './ScheduleSelect';
 import { Schedule } from '@/types/activityDetailType';
 
@@ -14,6 +15,17 @@ interface ScheduleSelectFormProps {
   ) => void;
 }
 
+function isPastDate(dateStr: string) {
+  const selected = new Date(dateStr);
+  const today = new Date();
+  today.setHours(0, 0, 0, 0);
+  return selected < today;
+}
+
+function isInvalidTimeRange(start: string, end: string) {
+  return start >= end;
+}
+
 export function ScheduleSelectForm({
   dates,
   onAddDate,
@@ -23,17 +35,18 @@ export function ScheduleSelectForm({
   return (
     <div className='space-y-4 pt-24'>
       <div className='flex flex-row items-center justify-between gap-5'>
-        <p className='text-xl text-black font-bold'>예약 가능한 시간대</p>
+        <p className='text-xl font-bold text-black'>예약 가능한 시간대</p>
         <div>
           <button
             type='button'
             onClick={onAddDate}
-            className='w-44 h-44 rounded-[10px] bg-green-300 px-10 py-5 hover:bg-green-600'
+            className='h-44 w-44 rounded-[10px] bg-green-300 px-10 py-5 hover:bg-green-600'
           >
             <p className='text-2xl font-bold text-white'>+</p>
           </button>
         </div>
       </div>
+
       {dates.map((dateSlot, idx) => (
         <div key={dateSlot.id ?? idx} className='flex'>
           <ScheduleSelect
@@ -41,20 +54,35 @@ export function ScheduleSelectForm({
             isRemovable={dates.length > 1}
             onAddDate={onAddDate}
             onRemove={onRemoveDate}
-            onDateChange={(index, value) => onDateChange(index, 'date', value)}
-            onStartTimeChange={(index, value) =>
-              onDateChange(index, 'startTime', value)
-            }
-            onEndTimeChange={(index, value) =>
-              onDateChange(index, 'endTime', value)
-            }
+            onDateChange={(index, value) => {
+              if (isPastDate(value)) {
+                toast.error('오늘 이전 날짜는 선택할 수 없습니다.');
+                return;
+              }
+              onDateChange(index, 'date', value);
+            }}
+            onStartTimeChange={(index, value) => {
+              const end = dates[index].endTime;
+              if (end && isInvalidTimeRange(value, end)) {
+                toast.error('시작 시간은 종료 시간보다 빨라야 합니다.');
+                return;
+              }
+              onDateChange(index, 'startTime', value);
+            }}
+            onEndTimeChange={(index, value) => {
+              const start = dates[index].startTime;
+              if (start && isInvalidTimeRange(start, value)) {
+                toast.error('종료 시간은 시작 시간보다 늦어야 합니다.');
+                return;
+              }
+              onDateChange(index, 'endTime', value);
+            }}
             date={dateSlot.date}
             startTime={dateSlot.startTime}
             endTime={dateSlot.endTime}
           />
         </div>
       ))}
-      
     </div>
   );
 }
diff --git a/src/app/(with-header)/myactivity/utils/dateValidatoin.ts b/src/app/(with-header)/myactivity/utils/dateValidatoin.ts
new file mode 100644
index 00000000..6aa91ce6
--- /dev/null
+++ b/src/app/(with-header)/myactivity/utils/dateValidatoin.ts
@@ -0,0 +1,31 @@
+import { Schedule } from '@/types/activityDetailType';
+
+export function validateSchedules(schedules: Schedule[]) {
+  const today = new Date();
+  today.setHours(0, 0, 0, 0);
+
+  for (let i = 0; i < schedules.length; i++) {
+    const { date, startTime, endTime } = schedules[i];
+
+    if (!date || !startTime || !endTime) {
+      return `날짜와 시간이 모두 입력되어야 합니다!`;
+    }
+
+    const selectedDate = new Date(date);
+    if (selectedDate < today) {
+      return `오늘보다 이전 날짜는 선택할 수 없습니다!`;
+    }
+
+    const [startHour, startMinute] = startTime.split(':').map(Number);
+    const [endHour, endMinute] = endTime.split(':').map(Number);
+
+    const startMinutes = startHour * 60 + startMinute;
+    const endMinutes = endHour * 60 + endMinute;
+
+    if (startMinutes >= endMinutes) {
+      return `종료 시간은 시작 시간보다 늦어야 합니다!`;
+    }
+  }
+
+  return null;
+}