diff --git a/src/Controller/Booking/Create/Step2Controller.php b/src/Controller/Booking/Create/Step2Controller.php
index e43d262..a72fa01 100644
--- a/src/Controller/Booking/Create/Step2Controller.php
+++ b/src/Controller/Booking/Create/Step2Controller.php
@@ -94,8 +94,10 @@ class Step2Controller extends AbstractController
             return $this->hxRedirect($request, $this->generateUrl('app_booking_create_step_3'));
         }
 
-        // Generate cards data
-        $cardsData = $this->generateAllCardsData($bookingCreateDto);
+        // Generate cards data with validation state if form was submitted and failed
+        $cardsData = (true === $form->isSubmitted() && false === $form->isValid())
+            ? $this->participantCardService->getAllCardsDataWithValidation($bookingCreateDto, ['booking_create'])
+            : $this->generateAllCardsData($bookingCreateDto);
 
         // Calculate summary data
         $summaryData = $this->calculateSummaryData($bookingCreateDto);
diff --git a/src/Service/ParticipantCardDataService.php b/src/Service/ParticipantCardDataService.php
index e848226..637f95d 100644
--- a/src/Service/ParticipantCardDataService.php
+++ b/src/Service/ParticipantCardDataService.php
@@ -5,6 +5,8 @@ declare(strict_types=1);
 namespace App\Service;
 
 use App\Form\Model\BookingDto;
+use App\Form\Model\ParticipantEditDto;
+use Symfony\Component\Validator\Validator\ValidatorInterface;
 
 /**
  * Extracts card display data for participants in card-based booking flows.
@@ -16,13 +18,14 @@ class ParticipantCardDataService
 {
     public function __construct(
         private readonly BookingPriceCalculatorService $priceCalculator,
+        private readonly ValidatorInterface $validator,
     ) {
     }
 
     /**
      * Get card data for a single participant.
      *
-     * @return array{name: string, roomName: string, price: string}
+     * @return array{name: string, roomName: string, price: string, isCanceled: bool}
      */
     public function getCardData(BookingDto $bookingDto, int $index): array
     {
@@ -41,17 +44,21 @@ class ParticipantCardDataService
         // Calculate and format individual price
         $price = $this->getFormattedPrice($bookingDto, $index);
 
+        // Check if participant is canceled
+        $isCanceled = $participant->isCanceled();
+
         return [
             'name' => $name,
             'roomName' => $roomName,
             'price' => $price,
+            'isCanceled' => $isCanceled,
         ];
     }
 
     /**
      * Get card data for all participants.
      *
-     * @return array<int, array{name: string, roomName: string, price: string}>
+     * @return array<int, array{name: string, roomName: string, price: string, isCanceled: bool}>
      */
     public function getAllCardsData(BookingDto $bookingDto): array
     {
@@ -121,4 +128,59 @@ class ParticipantCardDataService
 
         return number_format($price, 2, ',', '.').' €';
     }
+
+    /**
+     * Get card data for a single participant with validation state.
+     *
+     * @return array{name: string, roomName: string, price: string, isCanceled: bool, isValid: bool, errorMessages: array<string>}
+     */
+    public function getCardDataWithValidation(BookingDto $bookingDto, int $index, array $validationGroups): array
+    {
+        $participant = $bookingDto->participants[$index] ?? null;
+
+        if (null === $participant) {
+            throw new \InvalidArgumentException(sprintf('Participant at index %d does not exist', $index));
+        }
+
+        // Get basic card data
+        $cardData = $this->getCardData($bookingDto, $index);
+
+        // Wrap participant for validation
+        $wrapper = new ParticipantEditDto(
+            participant: $participant,
+            bookingContext: $bookingDto,
+        );
+
+        // Validate the wrapper DTO
+        $violations = $this->validator->validate($wrapper, null, $validationGroups);
+
+        // Extract validation state
+        $isValid = 0 === count($violations);
+        $errorMessages = [];
+
+        foreach ($violations as $violation) {
+            $errorMessages[] = $violation->getMessage();
+        }
+
+        return array_merge($cardData, [
+            'isValid' => $isValid,
+            'errorMessages' => $errorMessages,
+        ]);
+    }
+
+    /**
+     * Get card data for all participants with validation state.
+     *
+     * @return array<int, array{name: string, roomName: string, price: string, isCanceled: bool, isValid: bool, errorMessages: array<string>}>
+     */
+    public function getAllCardsDataWithValidation(BookingDto $bookingDto, array $validationGroups): array
+    {
+        $cardsData = [];
+
+        foreach ($bookingDto->participants as $index => $participant) {
+            $cardsData[$index] = $this->getCardDataWithValidation($bookingDto, $index, $validationGroups);
+        }
+
+        return $cardsData;
+    }
 }
diff --git a/templates/booking/_participant_card.html.twig b/templates/booking/_participant_card.html.twig
index b8413b3..fcaec11 100644
--- a/templates/booking/_participant_card.html.twig
+++ b/templates/booking/_participant_card.html.twig
@@ -1,8 +1,7 @@
 {# Compact participant card with name, room, price, and edit button #}
-{% set isCanceled = isCanceled|default(false) %}
-{% set hasErrors = hasErrors|default(false) %}
-{% set isValid = true %}
-{% set errorMessages = errorMessages|default([]) %}
+{% set isCanceled = cardData.isCanceled is defined ? cardData.isCanceled : false %}
+{% set isValid = cardData.isValid is defined ? cardData.isValid : true %}
+{% set errorMessages = cardData.errorMessages|default([]) %}
 {% set mode = mode|default('create') %}
 
 <div id="participant-card-{{ index }}"
diff --git a/templates/booking/_participant_form.html.twig b/templates/booking/_participant_form.html.twig
index f4438f5..39d5e76 100644
--- a/templates/booking/_participant_form.html.twig
+++ b/templates/booking/_participant_form.html.twig
@@ -60,14 +60,7 @@
 
             {# Contact information #}
             <div class="grid grid-cols-2 gap-4">
-                {{ form_row(form.email, {
-                    'attr': {
-                        'hx-trigger': 'change',
-                        'hx-post': path(refreshRouteName, refreshRouteParams|default({index: participantIndex})),
-                        'hx-target': '#main-content',
-                        'hx-swap': 'innerHTML'
-                    }
-                }) }}
+                {{ form_row(form.email) }}
                 {{ form_row(form.mobile) }}
             </div>
 
diff --git a/templates/booking/create/step_2.html.twig b/templates/booking/create/step_2.html.twig
index 4e4f27b..398ec38 100644
--- a/templates/booking/create/step_2.html.twig
+++ b/templates/booking/create/step_2.html.twig
@@ -9,6 +9,8 @@
         {% block participant_cards %}
         <div id="main-content" class="col-span-2">
             {{ form_start(form, {
+                'method': 'POST',
+                'action': path('app_booking_create_step_2'),
                 'attr': {
                     'hx-post': path('app_booking_create_step_2'),
                     'hx-target': '#main-content',
diff --git a/tests/Service/ParticipantCardDataServiceTest.php b/tests/Service/ParticipantCardDataServiceTest.php
index 7374ce1..6e72d67 100644
--- a/tests/Service/ParticipantCardDataServiceTest.php
+++ b/tests/Service/ParticipantCardDataServiceTest.php
@@ -11,16 +11,19 @@ use App\Form\Model\ParticipantDto;
 use App\Service\BookingPriceCalculatorService;
 use App\Service\ParticipantCardDataService;
 use PHPUnit\Framework\TestCase;
+use Symfony\Component\Validator\Validator\ValidatorInterface;
 
 class ParticipantCardDataServiceTest extends TestCase
 {
     private ParticipantCardDataService $service;
     private BookingPriceCalculatorService $priceCalculator;
+    private ValidatorInterface $validator;
 
     protected function setUp(): void
     {
         $this->priceCalculator = $this->createMock(BookingPriceCalculatorService::class);
-        $this->service = new ParticipantCardDataService($this->priceCalculator);
+        $this->validator = $this->createMock(ValidatorInterface::class);
+        $this->service = new ParticipantCardDataService($this->priceCalculator, $this->validator);
     }
 
     public function testGetCardDataWithFullParticipantData(): void
@@ -347,4 +350,134 @@ class ParticipantCardDataServiceTest extends TestCase
         $this->assertEquals('Teilnehmer:in 1', $result2['name']);
         $this->assertEquals('Teilnehmer:in 2', $result3['name']);
     }
+
+    public function testGetCardDataWithValidationReturnsValidCard(): void
+    {
+        $room = new Room();
+        $room->id = 1;
+        $room->label = 'Doppelzimmer';
+
+        $travel = new Travel();
+        $travel->rooms = [$room];
+
+        $participant = new ParticipantDto();
+        $participant->firstName = 'Max';
+        $participant->lastName = 'Mustermann';
+        $participant->assignedRoomId = 1;
+        $participant->email = 'max@example.com';
+
+        $bookingDto = new BookingDto($travel, 1);
+        $bookingDto->participants = [$participant];
+
+        $this->priceCalculator
+            ->method('calculateAllParticipantIndividualPrices')
+            ->willReturn([450.50]);
+
+        // Mock validator to return no violations (valid)
+        $violations = $this->createMock(\Symfony\Component\Validator\ConstraintViolationListInterface::class);
+        $violations->expects($this->once())
+            ->method('count')
+            ->willReturn(0);
+
+        $this->validator
+            ->expects($this->once())
+            ->method('validate')
+            ->willReturn($violations);
+
+        $result = $this->service->getCardDataWithValidation($bookingDto, 0, ['booking_create']);
+
+        $this->assertEquals('Max Mustermann', $result['name']);
+        $this->assertEquals('Doppelzimmer', $result['roomName']);
+        $this->assertEquals('450,50 €', $result['price']);
+        $this->assertTrue($result['isValid']);
+        $this->assertEmpty($result['errorMessages']);
+    }
+
+    public function testGetCardDataWithValidationReturnsInvalidCard(): void
+    {
+        $travel = new Travel();
+        $travel->rooms = [];
+
+        $participant = new ParticipantDto();
+        $participant->firstName = 'Max';
+        $participant->lastName = 'Mustermann';
+        $participant->email = 'duplicate@example.com';
+
+        $bookingDto = new BookingDto($travel, 1);
+        $bookingDto->participants = [$participant];
+
+        $this->priceCalculator
+            ->method('calculateAllParticipantIndividualPrices')
+            ->willReturn([0.0]);
+
+        // Mock validator to return violations (invalid)
+        $violation = $this->createMock(\Symfony\Component\Validator\ConstraintViolationInterface::class);
+        $violation->expects($this->once())
+            ->method('getMessage')
+            ->willReturn('Diese E-Mail Adresse wird bereits von einem anderen Teilnehmer verwendet');
+
+        // Use ConstraintViolationList directly instead of mocking
+        $violations = new \Symfony\Component\Validator\ConstraintViolationList([$violation]);
+
+        $this->validator
+            ->expects($this->once())
+            ->method('validate')
+            ->willReturn($violations);
+
+        $result = $this->service->getCardDataWithValidation($bookingDto, 0, ['booking_create']);
+
+        $this->assertEquals('Max Mustermann', $result['name']);
+        $this->assertFalse($result['isValid']);
+        $this->assertCount(1, $result['errorMessages']);
+        $this->assertEquals('Diese E-Mail Adresse wird bereits von einem anderen Teilnehmer verwendet', $result['errorMessages'][0]);
+    }
+
+    public function testGetAllCardsDataWithValidationReturnsAllCards(): void
+    {
+        $room = new Room();
+        $room->id = 1;
+        $room->label = 'Doppelzimmer';
+
+        $travel = new Travel();
+        $travel->rooms = [$room];
+
+        $participant1 = new ParticipantDto();
+        $participant1->firstName = 'Max';
+        $participant1->lastName = 'Mustermann';
+        $participant1->assignedRoomId = 1;
+        $participant1->email = 'max@example.com';
+
+        $participant2 = new ParticipantDto();
+        $participant2->firstName = 'Anna';
+        $participant2->lastName = 'Schmidt';
+        $participant2->assignedRoomId = 1;
+        $participant2->email = 'anna@example.com';
+
+        $bookingDto = new BookingDto($travel, 1);
+        $bookingDto->participants = [$participant1, $participant2];
+
+        $this->priceCalculator
+            ->expects($this->exactly(2))
+            ->method('calculateAllParticipantIndividualPrices')
+            ->willReturn([450.0, 500.0]);
+
+        // Mock validator to return no violations for both participants
+        $violations = $this->createMock(\Symfony\Component\Validator\ConstraintViolationListInterface::class);
+        $violations->expects($this->exactly(2))
+            ->method('count')
+            ->willReturn(0);
+
+        $this->validator
+            ->expects($this->exactly(2))
+            ->method('validate')
+            ->willReturn($violations);
+
+        $result = $this->service->getAllCardsDataWithValidation($bookingDto, ['booking_create']);
+
+        $this->assertCount(2, $result);
+        $this->assertTrue($result[0]['isValid']);
+        $this->assertTrue($result[1]['isValid']);
+        $this->assertEquals('Max Mustermann', $result[0]['name']);
+        $this->assertEquals('Anna Schmidt', $result[1]['name']);
+    }
 }