diff --git a/frontend/src/components/DashboardCalendar.vue b/frontend/src/components/DashboardCalendar.vue
index 5ac89ae..7f21bba 100644
--- a/frontend/src/components/DashboardCalendar.vue
+++ b/frontend/src/components/DashboardCalendar.vue
@@ -60,7 +60,7 @@ import type { CalendarOptions, EventInput, DatesSetArg, EventDropArg } from '@fu
 import { bookingsApi, adminBookingsApi, handleApiError } from '@/services/api'
 import { useAuthStore } from '@/stores/auth'
 import { useIsMobile } from '@/composables/useMediaQuery'
-import { formatDateTime as formatDateTimeUtil } from '@/utils/datetime'
+import { formatDateTime as formatDateTimeUtil, ensureUTC } from '@/utils/datetime'
 import BookingPreviewModal from '@/components/BookingPreviewModal.vue'
 import type { Booking } from '@/types'
 
@@ -126,8 +126,8 @@ const events = computed<EventInput[]>(() => {
   return bookings.value.map((booking) => ({
     id: String(booking.id),
     title: booking.space?.name ? `${booking.space.name} - ${booking.title}` : booking.title,
-    start: booking.start_datetime,
-    end: booking.end_datetime,
+    start: ensureUTC(booking.start_datetime),
+    end: ensureUTC(booking.end_datetime),
     backgroundColor: STATUS_COLORS[booking.status] || '#9E9E9E',
     borderColor: STATUS_COLORS[booking.status] || '#9E9E9E',
     extendedProps: {
diff --git a/frontend/src/components/SpaceCalendar.vue b/frontend/src/components/SpaceCalendar.vue
index 653a79f..a04fec8 100644
--- a/frontend/src/components/SpaceCalendar.vue
+++ b/frontend/src/components/SpaceCalendar.vue
@@ -61,7 +61,7 @@ import type { CalendarOptions, EventInput, DatesSetArg, EventDropArg } from '@fu
 import type { EventResizeDoneArg } from '@fullcalendar/interaction'
 import { bookingsApi, adminBookingsApi, handleApiError } from '@/services/api'
 import { useAuthStore } from '@/stores/auth'
-import { formatDateTime as formatDateTimeUtil } from '@/utils/datetime'
+import { formatDateTime as formatDateTimeUtil, ensureUTC } from '@/utils/datetime'
 import { useIsMobile } from '@/composables/useMediaQuery'
 import BookingPreviewModal from '@/components/BookingPreviewModal.vue'
 import type { Booking } from '@/types'
@@ -136,8 +136,8 @@ const events = computed<EventInput[]>(() => {
   return bookings.value.map((booking) => ({
     id: String(booking.id),
     title: booking.title,
-    start: booking.start_datetime,
-    end: booking.end_datetime,
+    start: ensureUTC(booking.start_datetime),
+    end: ensureUTC(booking.end_datetime),
     backgroundColor: STATUS_COLORS[booking.status] || '#9E9E9E',
     borderColor: STATUS_COLORS[booking.status] || '#9E9E9E',
     extendedProps: {