diff --git a/src/reservations/controller.ts b/src/reservations/controller.ts
index 40a2a06..ed6b569 100644
--- a/src/reservations/controller.ts
+++ b/src/reservations/controller.ts
@@ -16,6 +16,7 @@ import { Transform } from 'class-transformer'
 import {
 	IsArray,
 	IsBoolean,
+	IsDateString,
 	IsEnum,
 	IsOptional,
 	IsString,
@@ -57,10 +58,12 @@ export class CreateReservationRequest {
 	readonly ownerId: string
 
 	@Transform(DayjsTransformer)
+	@IsDateString()
 	readonly dateRangeStart: Dayjs
 
 	@IsOptional()
 	@Transform(DayjsTransformer)
+	@IsDateString()
 	readonly dateRangeEnd?: Dayjs
 
 	@IsOptional()