diff --git a/packages/platform/atoms/booker/BookerPlatformWrapper.tsx b/packages/platform/atoms/booker/BookerPlatformWrapper.tsx
index 444c573a6d..c779f0bb93 100644
--- a/packages/platform/atoms/booker/BookerPlatformWrapper.tsx
+++ b/packages/platform/atoms/booker/BookerPlatformWrapper.tsx
@@ -249,7 +249,7 @@ export const BookerPlatformWrapper = (
     eventTypeId: event?.data?.id ?? 0,
     startTime,
     endTime,
-    timeZone: session?.data?.timeZone,
+    timeZone: timezone,
     duration: selectedDuration ?? undefined,
     rescheduleUid: props.rescheduleUid,
     ...(props.isTeamEvent
@@ -336,7 +336,7 @@ export const BookerPlatformWrapper = (
     }))
   );
   const { data: overlayBusyDates } = useCalendarsBusyTimes({
-    loggedInUsersTz: session?.data?.timeZone || "Europe/London",
+    loggedInUsersTz: timezone,
     dateFrom: selectedDate,
     dateTo: selectedDate,
     calendarsToLoad: latestCalendarsToLoad,