diff --git a/packages/core/getUserAvailability.ts b/packages/core/getUserAvailability.ts
index 1555766da62966..8d09d423791e1f 100644
--- a/packages/core/getUserAvailability.ts
+++ b/packages/core/getUserAvailability.ts
@@ -22,8 +22,7 @@ import { safeStringify } from "@calcom/lib/safeStringify";
 import { EventTypeRepository } from "@calcom/lib/server/repository/eventType";
 import { UserRepository } from "@calcom/lib/server/repository/user";
 import prisma from "@calcom/prisma";
-import { SchedulingType } from "@calcom/prisma/enums";
-import { BookingStatus } from "@calcom/prisma/enums";
+import { BookingStatus, SchedulingType } from "@calcom/prisma/enums";
 import { EventTypeMetaDataSchema, stringToDayjsZod } from "@calcom/prisma/zod-utils";
 import type { EventBusyDetails, IntervalLimitUnit } from "@calcom/types/Calendar";
 import type { TimeRange } from "@calcom/types/schedule";
@@ -547,7 +546,7 @@ const _getUserAvailability = async function getUsersWorkingHoursLifeTheUniverseA
       },
     }));
 
-  const datesOutOfOffice: IOutOfOfficeData = calculateOutOfOfficeRanges(outOfOfficeDays, availability);
+  const datesOutOfOffice: IOutOfOfficeData = await calculateOutOfOfficeRanges(outOfOfficeDays, availability);
 
   const { dateRanges, oooExcludedDateRanges } = buildDateRanges({
     dateFrom,
@@ -636,15 +635,17 @@ export interface IOutOfOfficeData {
   };
 }
 
-const calculateOutOfOfficeRanges = (
+const calculateOutOfOfficeRanges = async (
   outOfOfficeDays: GetUserAvailabilityInitialData["outOfOfficeDays"],
   availability: GetUserAvailabilityParamsDTO["availability"]
-): IOutOfOfficeData => {
+): Promise<IOutOfOfficeData> => {
   if (!outOfOfficeDays || outOfOfficeDays.length === 0) {
     return {};
   }
 
-  return outOfOfficeDays.reduce((acc: IOutOfOfficeData, { start, end, toUser, user, reason }) => {
+  const acc: IOutOfOfficeData = {};
+
+  for (const { start, end, toUser, user, reason } of outOfOfficeDays) {
     // here we should use startDate or today if start is before today
     // consider timezone in start and end date range
     const startDateRange = dayjs(start).utc().isBefore(dayjs().startOf("day").utc())
@@ -665,19 +666,27 @@ const calculateOutOfOfficeRanges = (
         continue; // Skip to the next iteration if day not found in flattenDays
       }
 
+      const enrichedToUser = toUser ? await UserRepository.enrichUserWithItsProfile({ user: toUser }) : null;
+
       acc[date.format("YYYY-MM-DD")] = {
         // @TODO:  would be good having start and end availability time here, but for now should be good
         // you can obtain that from user availability defined outside of here
         fromUser: { id: user.id, displayName: user.name },
         // optional chaining destructuring toUser
-        toUser: !!toUser ? { id: toUser.id, displayName: toUser.name, username: toUser.username } : null,
+        ...(!!enrichedToUser && {
+          toUser: {
+            id: enrichedToUser.id,
+            username: enrichedToUser.username,
+            displayName: enrichedToUser.name,
+          },
+        }),
         reason: !!reason ? reason.reason : null,
         emoji: !!reason ? reason.emoji : null,
       };
     }
+  }
 
-    return acc;
-  }, {});
+  return acc;
 };
 
 type GetUsersAvailabilityProps = {
diff --git a/packages/lib/slots.ts b/packages/lib/slots.ts
index 645c71fa0abdb2..94a087c9278de1 100644
--- a/packages/lib/slots.ts
+++ b/packages/lib/slots.ts
@@ -184,6 +184,7 @@ function buildSlotsWithDateRanges({
     }
   }
 
+  const processedOOODates = new Set<string>();
   dateRanges.forEach((range) => {
     const dateYYYYMMDD = range.start.format("YYYY-MM-DD");
     const startTimeWithMinNotice = dayjs.utc().add(minimumBookingNotice, "minute");
@@ -206,6 +207,25 @@ function buildSlotsWithDateRanges({
 
     slotStartTime = slotStartTime.add(offsetStart ?? 0, "minutes").tz(timeZone);
 
+    // Add OOO slot if exists and is before current range
+    if (datesOutOfOffice) {
+      Object.entries(datesOutOfOffice).forEach(([dateStr, oooData]) => {
+        const oooDate = dayjs(dateStr);
+        if (oooDate.isBefore(dateYYYYMMDD, "day") && !processedOOODates.has(dateStr)) {
+          slots.push({
+            time: oooDate.startOf("day"),
+            away: true,
+            ...(oooData.fromUser && { fromUser: oooData.fromUser }),
+            ...(oooData.toUser && { toUser: oooData.toUser }),
+            ...(oooData.reason && { reason: oooData.reason }),
+            ...(oooData.emoji && { emoji: oooData.emoji }),
+          });
+          // when the date range increases in the next iteration, we don't want to process this date again
+          processedOOODates.add(dateStr);
+        }
+      });
+    }
+
     while (!slotStartTime.add(eventLength, "minutes").subtract(1, "second").utc().isAfter(rangeEnd)) {
       const dateOutOfOfficeExists = datesOutOfOffice?.[dateYYYYMMDD];
       let slotData: {
@@ -231,8 +251,8 @@ function buildSlotsWithDateRanges({
           ...(reason && { reason }),
           ...(emoji && { emoji }),
         };
+        processedOOODates.add(dateYYYYMMDD);
       }
-
       slots.push(slotData);
       slotStartTime = slotStartTime.add(frequency + (offsetStart ?? 0), "minutes");
     }