diff --git a/doc/admin-spec.yaml b/doc/admin-spec.yaml
index 1ebd213..25a969b 100644
--- a/doc/admin-spec.yaml
+++ b/doc/admin-spec.yaml
@@ -679,7 +679,7 @@ components:
         - title
         - startTime
         - endTime
-        - roomId
+        - speakerIds
       properties:
         title:
           type: string
@@ -697,7 +697,6 @@ components:
           format: uuid
         capacity:
           type: integer
-          minimum: 0
         speakerIds:
           type: array
           items:
@@ -710,7 +709,7 @@ components:
         - title
         - startTime
         - endTime
-        - roomId
+        - speakerIds
       properties:
         title:
           type: string
@@ -728,7 +727,6 @@ components:
           format: uuid
         capacity:
           type: integer
-          minimum: 0
         speakerIds:
           type: array
           items:
diff --git a/src/main/java/org/onlydevs/hibento/endpoint/rest/controller/GlobalExceptionHandler.java b/src/main/java/org/onlydevs/hibento/endpoint/rest/controller/GlobalExceptionHandler.java
index 1fb122a..e8cae61 100644
--- a/src/main/java/org/onlydevs/hibento/endpoint/rest/controller/GlobalExceptionHandler.java
+++ b/src/main/java/org/onlydevs/hibento/endpoint/rest/controller/GlobalExceptionHandler.java
@@ -12,6 +12,7 @@
 import org.springframework.http.ResponseEntity;
 import org.springframework.http.converter.HttpMessageNotReadableException;
 import org.springframework.security.access.AccessDeniedException;
+import org.springframework.web.bind.MethodArgumentNotValidException;
 import org.springframework.web.bind.MissingServletRequestParameterException;
 import org.springframework.web.bind.annotation.ExceptionHandler;
 import org.springframework.web.bind.annotation.RestControllerAdvice;
@@ -76,6 +77,16 @@ public ResponseEntity<ErrorResponse> handleMessageNotReadable(
     return ResponseEntity.status(BAD_REQUEST).body(new ErrorResponse("Malformed request body"));
   }
 
+  @ExceptionHandler(MethodArgumentNotValidException.class)
+  public ResponseEntity<ErrorResponse> handleValidation(MethodArgumentNotValidException ex) {
+    var message =
+        ex.getBindingResult().getFieldErrors().stream()
+            .map(e -> e.getField() + ": " + e.getDefaultMessage())
+            .reduce((a, b) -> a + "; " + b)
+            .orElse("Validation failed");
+    return ResponseEntity.status(BAD_REQUEST).body(new ErrorResponse(message));
+  }
+
   @ExceptionHandler(AccessDeniedException.class)
   public ResponseEntity<ErrorResponse> handleAccessDenied(AccessDeniedException ex) {
     return ResponseEntity.status(FORBIDDEN)
diff --git a/src/main/java/org/onlydevs/hibento/endpoint/rest/controller/dto/request/CreateSession.java b/src/main/java/org/onlydevs/hibento/endpoint/rest/controller/dto/request/CreateSession.java
index 9a6cc6e..3948543 100644
--- a/src/main/java/org/onlydevs/hibento/endpoint/rest/controller/dto/request/CreateSession.java
+++ b/src/main/java/org/onlydevs/hibento/endpoint/rest/controller/dto/request/CreateSession.java
@@ -29,7 +29,6 @@ public class CreateSession {
   @NotNull(message = "End time is required")
   private Instant endTime;
 
-  @NotNull(message = "Room ID is required")
   private UUID roomId;
 
   private Integer capacity;
diff --git a/src/main/java/org/onlydevs/hibento/endpoint/rest/controller/dto/request/UpdateSession.java b/src/main/java/org/onlydevs/hibento/endpoint/rest/controller/dto/request/UpdateSession.java
index 8f026c7..a6c778d 100644
--- a/src/main/java/org/onlydevs/hibento/endpoint/rest/controller/dto/request/UpdateSession.java
+++ b/src/main/java/org/onlydevs/hibento/endpoint/rest/controller/dto/request/UpdateSession.java
@@ -29,7 +29,6 @@ public class UpdateSession {
   @NotNull(message = "End time is required")
   private Instant endTime;
 
-  @NotNull(message = "Room ID is required")
   private UUID roomId;
 
   private Integer capacity;
diff --git a/src/main/java/org/onlydevs/hibento/mapper/SessionMapper.java b/src/main/java/org/onlydevs/hibento/mapper/SessionMapper.java
index cc9252a..6fc5981 100644
--- a/src/main/java/org/onlydevs/hibento/mapper/SessionMapper.java
+++ b/src/main/java/org/onlydevs/hibento/mapper/SessionMapper.java
@@ -1,5 +1,6 @@
 package org.onlydevs.hibento.mapper;
 
+import java.util.UUID;
 import org.onlydevs.hibento.endpoint.rest.controller.dto.response.CreatedSession;
 import org.onlydevs.hibento.endpoint.rest.controller.dto.response.UpdatedSession;
 import org.onlydevs.hibento.model.EventSession;
@@ -8,6 +9,14 @@
 @Component
 public class SessionMapper {
 
+  private UUID nullableRoomId(EventSession session) {
+    return session.getRoom() != null ? session.getRoom().getId() : null;
+  }
+
+  private String nullableRoomName(EventSession session) {
+    return session.getRoom() != null ? session.getRoom().getName() : null;
+  }
+
   public CreatedSession toCreatedSession(EventSession session) {
     return new CreatedSession(
         session.getId(),
@@ -16,8 +25,8 @@ public CreatedSession toCreatedSession(EventSession session) {
         session.getDescription(),
         session.getStartTime(),
         session.getEndTime(),
-        session.getRoom().getId(),
-        session.getRoom().getName(),
+        nullableRoomId(session),
+        nullableRoomName(session),
         session.getCapacity(),
         session.getEventSessionSpeakers().stream().map(ess -> ess.getSpeaker().getId()).toList(),
         session.getCreatedAt(),
@@ -32,8 +41,8 @@ public UpdatedSession toUpdatedSession(EventSession session) {
         session.getDescription(),
         session.getStartTime(),
         session.getEndTime(),
-        session.getRoom().getId(),
-        session.getRoom().getName(),
+        nullableRoomId(session),
+        nullableRoomName(session),
         session.getCapacity(),
         session.getEventSessionSpeakers().stream().map(ess -> ess.getSpeaker().getId()).toList(),
         session.getCreatedAt(),
diff --git a/src/main/java/org/onlydevs/hibento/service/SessionService.java b/src/main/java/org/onlydevs/hibento/service/SessionService.java
index 72d54d1..d8a0848 100644
--- a/src/main/java/org/onlydevs/hibento/service/SessionService.java
+++ b/src/main/java/org/onlydevs/hibento/service/SessionService.java
@@ -43,14 +43,17 @@ public CreatedSession createSession(UUID eventId, CreateSession request) {
             .findById(eventId)
             .orElseThrow(() -> new NotFoundException("Event not found"));
 
-    Room room =
-        roomRepository
-            .findById(request.getRoomId())
-            .orElseThrow(() -> new NotFoundException("Room not found"));
-
-    if (sessionRepository.existsByRoomIdAndStartTimeLessThanEqualAndEndTimeGreaterThanEqual(
-        request.getRoomId(), request.getEndTime(), request.getStartTime())) {
-      throw new ConflictException("Room already has a session during this time");
+    Room room = null;
+    if (request.getRoomId() != null) {
+      room =
+          roomRepository
+              .findById(request.getRoomId())
+              .orElseThrow(() -> new NotFoundException("Room not found"));
+
+      if (sessionRepository.existsByRoomIdAndStartTimeLessThanEqualAndEndTimeGreaterThanEqual(
+          request.getRoomId(), request.getEndTime(), request.getStartTime())) {
+        throw new ConflictException("Room already has a session during this time");
+      }
     }
 
     EventSession session = new EventSession();
@@ -96,14 +99,18 @@ public UpdatedSession updateSession(UUID id, UpdateSession request) {
       throw new BadRequestException("Start time must be before end time");
     }
 
-    Room room =
-        roomRepository
-            .findById(request.getRoomId())
-            .orElseThrow(() -> new NotFoundException("Room not found"));
-
-    if (sessionRepository.existsByRoomIdAndStartTimeLessThanEqualAndEndTimeGreaterThanEqualAndIdNot(
-        request.getRoomId(), request.getEndTime(), request.getStartTime(), id)) {
-      throw new ConflictException("Room already has a session during this time");
+    Room room = session.getRoom();
+    if (request.getRoomId() != null) {
+      room =
+          roomRepository
+              .findById(request.getRoomId())
+              .orElseThrow(() -> new NotFoundException("Room not found"));
+
+      if (sessionRepository
+          .existsByRoomIdAndStartTimeLessThanEqualAndEndTimeGreaterThanEqualAndIdNot(
+              request.getRoomId(), request.getEndTime(), request.getStartTime(), id)) {
+        throw new ConflictException("Room already has a session during this time");
+      }
     }
 
     session.setTitle(request.getTitle());