diff --git a/src/Controller/Booking/CreateStep2Controller.php b/src/Controller/Booking/CreateStep2Controller.php
index 7d1ef6e..0bae619 100644
--- a/src/Controller/Booking/CreateStep2Controller.php
+++ b/src/Controller/Booking/CreateStep2Controller.php
@@ -10,6 +10,7 @@ use App\Form\Model\BookingCreateDto;
 use App\Form\Model\ParticipantDto;
 use App\Service\BookingPriceCalculatorService;
 use App\Service\BookingService;
+use App\Service\RoomAssignmentService;
 use App\Service\TravelDataService;
 use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
 use Symfony\Component\HttpFoundation\Request;
@@ -32,6 +33,7 @@ class CreateStep2Controller extends AbstractController
         private readonly BookingService $bookingService,
         private readonly BookingPriceCalculatorService $priceCalculator,
         private readonly TravelDataService $travelDataService,
+        private readonly RoomAssignmentService $roomAssignmentService,
     ) {
     }
 
@@ -59,6 +61,9 @@ class CreateStep2Controller extends AbstractController
         $this->ensureCorrectNumberOfParticipants($bookingCreateDto);
         $participantsCount = $this->getParticipantsCount($bookingCreateDto);
 
+        // Auto-assign participants to rooms if not already assigned
+        $this->autoAssignRoomsIfNeeded($bookingCreateDto);
+
         // Pre-select mandatory services for participants with birth dates
         $this->bookingService->preselectMandatoryServices($bookingCreateDto);
 
@@ -204,4 +209,28 @@ class CreateStep2Controller extends AbstractController
             $this->travelDataService->patchAvailabilities($bookingCreateDto->travel, $availabilities);
         }
     }
+
+    /**
+     * Automatically assigns participants to rooms if they don't have room assignments yet.
+     *
+     * This is called when entering Step 2 to ensure all participants have room assignments
+     * based on the selected rooms from Step 1. Only assigns if participants are unassigned.
+     *
+     * @param BookingCreateDto $bookingCreateDto The booking DTO with participants and room selections
+     */
+    private function autoAssignRoomsIfNeeded(BookingCreateDto $bookingCreateDto): void
+    {
+        // Check if any participants need room assignment
+        $needsAssignment = false;
+        foreach ($bookingCreateDto->participants as $participant) {
+            if (null === $participant->assignedRoomId) {
+                $needsAssignment = true;
+                break;
+            }
+        }
+
+        if ($needsAssignment) {
+            $this->roomAssignmentService->assignParticipantsToRooms($bookingCreateDto);
+        }
+    }
 }
diff --git a/src/Service/RoomAssignmentService.php b/src/Service/RoomAssignmentService.php
new file mode 100644
index 0000000..35021b3
--- /dev/null
+++ b/src/Service/RoomAssignmentService.php
@@ -0,0 +1,58 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Service;
+
+use App\Form\Model\BookingCreateDto;
+
+/**
+ * Handles automatic room assignment for booking participants.
+ *
+ * This service automatically assigns participants to selected rooms based on room capacity
+ * and quantity, eliminating the need for manual room selection in the booking flow.
+ */
+class RoomAssignmentService
+{
+    /**
+     * Automatically assigns participants to rooms based on selected room quantities and capacities.
+     *
+     * Assignment algorithm:
+     * - Iterates through selected rooms in order
+     * - For each room quantity, assigns minPax participants to that room ID
+     * - Ensures sequential assignment (participant 0, 1, 2, etc.)
+     *
+     * Example:
+     * - 2x "Doppelzimmer" (capacity 2) = participants 0-1 → room A, participants 2-3 → room A
+     * - 1x "3-Bett-Zimmer" (capacity 3) = participants 4-6 → room B
+     *
+     * @param BookingCreateDto $dto The booking DTO containing room selections and participants
+     */
+    public function assignParticipantsToRooms(BookingCreateDto $dto): void
+    {
+        $participantIndex = 0;
+        $selectedRooms = $dto->getSelectedRooms();
+        $availableRooms = $dto->travel->getAvailableRooms();
+
+        foreach ($selectedRooms as $roomSelection) {
+            $room = $availableRooms[$roomSelection->roomId] ?? null;
+
+            if (null === $room) {
+                continue; // Skip if room not found
+            }
+
+            $capacityPerRoom = $room->minPax ?? 1;
+
+            // Assign participants for each room quantity
+            for ($i = 0; $i < $roomSelection->quantity; ++$i) {
+                // Assign participants according to room capacity
+                for ($j = 0; $j < $capacityPerRoom; ++$j) {
+                    if (isset($dto->participants[$participantIndex])) {
+                        $dto->participants[$participantIndex]->assignedRoomId = $room->id;
+                        ++$participantIndex;
+                    }
+                }
+            }
+        }
+    }
+}