diff --git a/src/Service/BookingEditDataLoaderService.php b/src/Service/BookingEditDataLoaderService.php
index c231d21..0831c3c 100644
--- a/src/Service/BookingEditDataLoaderService.php
+++ b/src/Service/BookingEditDataLoaderService.php
@@ -75,8 +75,8 @@ class BookingEditDataLoaderService
         }
 
         $mutableData = $this->travelDataService->getMutabilityData($bookingData->dateId);
-        // Using cached: true populates the cache for subsequent participant form loads
-        $availabilities = $this->travelDataService->getAvailabilityData($bookingData->dateId, cached: true);
+        // Force refresh ensures fresh data at edit start, then populates cache for subsequent loads
+        $availabilities = $this->travelDataService->getAvailabilityData($bookingData->dateId, cached: true, forceRefresh: true);
 
         if (null === $mutableData || null === $availabilities) {
             return null;
diff --git a/src/Service/BookingService.php b/src/Service/BookingService.php
index dbb83d7..ac0b406 100644
--- a/src/Service/BookingService.php
+++ b/src/Service/BookingService.php
@@ -236,8 +236,8 @@ class BookingService
         }
 
         // Fetch and patch availability data (includes allowedBookingStatus from API)
-        // Using cached: true populates the cache for subsequent participant form loads
-        $availabilities = $this->travelDataService->getAvailabilityData($dateId, cached: true);
+        // Force refresh ensures fresh data at booking start, then populates cache for subsequent loads
+        $availabilities = $this->travelDataService->getAvailabilityData($dateId, cached: true, forceRefresh: true);
         if (null !== $availabilities) {
             $this->travelDataService->patchAvailabilities($travelData, $availabilities);
         }
diff --git a/src/Service/TravelDataService.php b/src/Service/TravelDataService.php
index 03ea4b0..2edf2df 100644
--- a/src/Service/TravelDataService.php
+++ b/src/Service/TravelDataService.php
@@ -33,6 +33,7 @@ class TravelDataService
 {
     public const SOURCE_LOCAL = 'local';
     public const SOURCE_REMOTE = 'remote';
+    private const AVAILABILITY_CACHE_TTL = 600;
 
     public function __construct(
         private readonly TravelLoader $travelLoader,
@@ -522,20 +523,24 @@ class TravelDataService
     /**
      * Gets availability data for a travel date.
      *
-     * @param int  $dateId The travel date ID for API call
-     * @param bool $cached Whether to use cached data (default: false, TTL when cached: 600 seconds)
-     * @param int  $ttl    Cache TTL in seconds when $cached is true (default: 600 seconds)
+     * @param int  $dateId       The travel date ID for API call
+     * @param bool $cached       Whether to use cached data (default: false)
+     * @param bool $forceRefresh Whether to invalidate cache before fetching (requires cached: true)
      *
      * @return ServiceAvailabilityResponse|null The availability data or null if not available or error occurred
      */
-    public function getAvailabilityData(int $dateId, bool $cached = false, int $ttl = 600): ?ServiceAvailabilityResponse
+    public function getAvailabilityData(int $dateId, bool $cached = false, bool $forceRefresh = false): ?ServiceAvailabilityResponse
     {
         if ($cached) {
             $cacheKey = sprintf('availability_%d', $dateId);
 
             try {
-                return $this->cache->get($cacheKey, function (ItemInterface $item) use ($dateId, $ttl) {
-                    $item->expiresAfter($ttl);
+                if ($forceRefresh) {
+                    $this->cache->delete($cacheKey);
+                }
+
+                return $this->cache->get($cacheKey, function (ItemInterface $item) use ($dateId) {
+                    $item->expiresAfter(self::AVAILABILITY_CACHE_TTL);
 
                     return $this->fetchAvailabilityData($dateId);
                 });