diff --git a/src/BusProNet/DataProcessor/BookingDataProcessor.php b/src/BusProNet/DataProcessor/BookingDataProcessor.php
index e782437..8f11a1f 100644
--- a/src/BusProNet/DataProcessor/BookingDataProcessor.php
+++ b/src/BusProNet/DataProcessor/BookingDataProcessor.php
@@ -105,6 +105,11 @@ class BookingDataProcessor
 
         // Update applicant's data with personal data of first participant
         if (false !== $firstParticipant = reset($bookingData->participants)) {
+            // Ensure valid nationality
+            if (true === empty($bookingData->applicant->nationality)) {
+                $bookingData->applicant->nationality = $firstParticipant->nationality;
+            }
+
             $bookingData->applicant->height = $firstParticipant->height;
             $bookingData->applicant->weight = $firstParticipant->weight;
             $bookingData->applicant->shoeSize = $firstParticipant->shoeSize;