diff --git a/src/BusProNet/Model/Address.php b/src/BusProNet/Model/Address.php
index a6a409d..85bb5d3 100644
--- a/src/BusProNet/Model/Address.php
+++ b/src/BusProNet/Model/Address.php
@@ -4,6 +4,8 @@ declare(strict_types=1);
 
 namespace App\BusProNet\Model;
 
+use Symfony\Component\Validator\Constraints as Assert;
+
 /**
  * Represents a physical address with street, postal code, city, and country information.
  *
@@ -13,14 +15,18 @@ namespace App\BusProNet\Model;
  */
 class Address
 {
+    #[Assert\NotBlank(message: 'Bitte angeben', groups: ['personal_data'])]
     public ?string $street = null;
 
+    #[Assert\NotBlank(message: 'Bitte angeben', groups: ['personal_data'])]
     public ?string $postCode = null;
 
+    #[Assert\NotBlank(message: 'Bitte angeben', groups: ['personal_data'])]
     public ?string $city = null;
 
     public ?string $district = null;
 
+    #[Assert\NotBlank(message: 'Bitte angeben', groups: ['personal_data'])]
     public ?string $country = null;
 
     /**
diff --git a/src/BusProNet/Model/PersonalData.php b/src/BusProNet/Model/PersonalData.php
index 881fdcb..57458de 100644
--- a/src/BusProNet/Model/PersonalData.php
+++ b/src/BusProNet/Model/PersonalData.php
@@ -31,11 +31,18 @@ class PersonalData
 
     public ?string $salutation = null;
     public ?string $title = null;
+
+    #[Assert\NotBlank(message: 'Bitte angeben', groups: ['personal_data'])]
+    #[Assert\Choice(choices: ['M', 'W', 'D'], message: 'Bitte gib einen gültigen Wert an', groups: ['personal_data'])]
     public ?string $gender = null;
+
+    #[Assert\NotBlank(message: 'Bitte angeben', groups: ['personal_data'])]
     public ?string $nationality = null;
     public ?string $height = null;
     public ?string $shoeSize = null;
     public ?string $weight = null;
+
+    #[Assert\NotBlank(message: 'Bitte angeben', groups: ['personal_data'])]
     public ?\DateTimeImmutable $dateOfBirth = null;
     public ?string $remarks = null;
 
diff --git a/src/Controller/Account/PersonalDataController.php b/src/Controller/Account/PersonalDataController.php
index 9bcdc08..0b3108d 100644
--- a/src/Controller/Account/PersonalDataController.php
+++ b/src/Controller/Account/PersonalDataController.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace App\Controller\Account;
 
 use App\BusProNet\ApiClient;
@@ -7,9 +9,11 @@ use App\BusProNet\Exception\ApiClientException;
 use App\BusProNet\Model\Notification;
 use App\BusProNet\Model\PersonalData;
 use App\Entity\User;
+use App\EventSubscriber\ProfileCompletionSubscriber;
 use App\Form\PersonalDataType;
 use App\Security\Crypt;
 use App\Service\BookingEditDataLoaderService;
+use App\Service\ProfileCompletenessChecker;
 use Psr\Log\LoggerInterface;
 use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
 use Symfony\Component\HttpFoundation\Request;
@@ -27,15 +31,17 @@ use Symfony\Component\Security\Http\Attribute\IsGranted;
 class PersonalDataController extends AbstractController
 {
     /**
-     * @param ApiClient                    $apiClient  BusProNet API client for data operations
-     * @param Crypt                        $crypt      Encryption service for password handling
-     * @param BookingEditDataLoaderService $dataLoader Data loader for cache invalidation
-     * @param LoggerInterface              $logger     Logger for audit trails and debugging
+     * @param ApiClient                    $apiClient           BusProNet API client for data operations
+     * @param Crypt                        $crypt               Encryption service for password handling
+     * @param BookingEditDataLoaderService $dataLoader          Data loader for cache invalidation
+     * @param ProfileCompletenessChecker   $completenessChecker Profile validation service
+     * @param LoggerInterface              $logger              Logger for audit trails and debugging
      */
     public function __construct(
         private readonly ApiClient $apiClient,
         private readonly Crypt $crypt,
         private readonly BookingEditDataLoaderService $dataLoader,
+        private readonly ProfileCompletenessChecker $completenessChecker,
         private readonly LoggerInterface $logger,
     ) {
     }
@@ -98,6 +104,16 @@ class PersonalDataController extends AbstractController
                 $this->logger->info('Updated personal data', [
                     'email' => $user->getEmail(),
                 ]);
+
+                // Handle profile completion redirect
+                $session = $request->getSession();
+                $redirectUrl = $session->get(ProfileCompletionSubscriber::SESSION_REDIRECT_KEY);
+
+                if (null !== $redirectUrl && true === $this->completenessChecker->isComplete($personalData)) {
+                    $session->remove(ProfileCompletionSubscriber::SESSION_REDIRECT_KEY);
+
+                    return $this->redirect($redirectUrl);
+                }
             } catch (ApiClientException $e) {
                 $this->addFlash('error', $e->getMessage());
             }
diff --git a/src/EventSubscriber/ProfileCompletionSubscriber.php b/src/EventSubscriber/ProfileCompletionSubscriber.php
new file mode 100644
index 0000000..514fcec
--- /dev/null
+++ b/src/EventSubscriber/ProfileCompletionSubscriber.php
@@ -0,0 +1,105 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\EventSubscriber;
+
+use App\BusProNet\ApiClient;
+use App\BusProNet\Exception\ApiClientException;
+use App\BusProNet\Model\PersonalData;
+use App\Entity\User;
+use App\Security\Crypt;
+use App\Service\ProfileCompletenessChecker;
+use Psr\Log\LoggerInterface;
+use Symfony\Component\EventDispatcher\EventSubscriberInterface;
+use Symfony\Component\HttpFoundation\RedirectResponse;
+use Symfony\Component\Routing\Generator\UrlGeneratorInterface;
+use Symfony\Component\Security\Http\Event\LoginSuccessEvent;
+
+/**
+ * Checks profile completeness after successful login and redirects to profile page if incomplete.
+ *
+ * This subscriber intercepts the login success flow to validate that users have complete
+ * profile data before proceeding. When incomplete profiles are detected, the original
+ * target URL is stored in the session and the user is redirected to complete their data.
+ */
+class ProfileCompletionSubscriber implements EventSubscriberInterface
+{
+    public const SESSION_REDIRECT_KEY = '_profile_completion_redirect';
+
+    public function __construct(
+        private readonly ApiClient $apiClient,
+        private readonly Crypt $crypt,
+        private readonly ProfileCompletenessChecker $completenessChecker,
+        private readonly UrlGeneratorInterface $urlGenerator,
+        private readonly LoggerInterface $logger,
+    ) {
+    }
+
+    public static function getSubscribedEvents(): array
+    {
+        // Use lower priority to run after the authenticator sets the response
+        return [
+            LoginSuccessEvent::class => ['onLoginSuccess', -10],
+        ];
+    }
+
+    public function onLoginSuccess(LoginSuccessEvent $event): void
+    {
+        $user = $event->getUser();
+
+        if (false === $user instanceof User) {
+            return;
+        }
+
+        $email = $user->getEmail();
+        $password = $this->crypt->decrypt($user->getPassword());
+
+        try {
+            $personalData = $this->apiClient->getPersonalData($email, $password);
+        } catch (ApiClientException $e) {
+            $this->logger->warning('Failed to fetch personal data for profile completeness check', [
+                'email' => $email,
+                'error' => $e->getMessage(),
+            ]);
+
+            return;
+        }
+
+        if (false === $personalData instanceof PersonalData) {
+            $this->logger->warning('Invalid response when fetching personal data for profile completeness check', [
+                'email' => $email,
+            ]);
+
+            return;
+        }
+
+        if (true === $this->completenessChecker->isComplete($personalData)) {
+            return;
+        }
+
+        $this->logger->info('Incomplete profile detected, redirecting to profile completion', [
+            'email' => $email,
+        ]);
+
+        $request = $event->getRequest();
+        $session = $request->getSession();
+
+        // Store the original target URL (from authenticator's response or target path)
+        $originalResponse = $event->getResponse();
+        $targetUrl = null;
+
+        if ($originalResponse instanceof RedirectResponse) {
+            $targetUrl = $originalResponse->getTargetUrl();
+        }
+
+        // Don't redirect back to the personal data page itself
+        $personalDataUrl = $this->urlGenerator->generate('app_personal_data');
+        if (null !== $targetUrl && $targetUrl !== $personalDataUrl) {
+            $session->set(self::SESSION_REDIRECT_KEY, $targetUrl);
+        }
+
+        // Override the response to redirect to personal data page
+        $event->setResponse(new RedirectResponse($personalDataUrl));
+    }
+}
diff --git a/src/Form/PersonalDataType.php b/src/Form/PersonalDataType.php
index 8afd71f..315a86f 100644
--- a/src/Form/PersonalDataType.php
+++ b/src/Form/PersonalDataType.php
@@ -1,9 +1,13 @@
 <?php
 
+declare(strict_types=1);
+
 namespace App\Form;
 
 use App\BusProNet\Form\CountryType;
 use Symfony\Component\Form\AbstractType;
+use Symfony\Component\Form\Extension\Core\Type\BirthdayType;
+use Symfony\Component\Form\Extension\Core\Type\ChoiceType;
 use Symfony\Component\Form\Extension\Core\Type\EmailType;
 use Symfony\Component\Form\Extension\Core\Type\TextType;
 use Symfony\Component\Form\FormBuilderInterface;
@@ -13,6 +17,23 @@ class PersonalDataType extends AbstractType
     public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
+            ->add('gender', ChoiceType::class, [
+                'label' => 'Gender',
+                'placeholder' => false,
+                'choices' => [
+                    'männlich' => 'M',
+                    'weiblich' => 'W',
+                    'divers' => 'D',
+                ],
+                'invalid_message' => 'Bitte gib einen gültigen Wert an',
+            ])
+            ->add('dateOfBirth', BirthdayType::class, [
+                'label' => 'Geburtsdatum',
+                'widget' => 'text',
+                'input' => 'datetime_immutable',
+                'html5' => false,
+                'invalid_message' => 'Bitte gib ein gültiges Datum ein',
+            ])
             ->add('street', TextType::class, [
                 'label' => 'Straße',
                 'property_path' => 'address.street',
diff --git a/src/Service/ProfileCompletenessChecker.php b/src/Service/ProfileCompletenessChecker.php
new file mode 100644
index 0000000..5abe652
--- /dev/null
+++ b/src/Service/ProfileCompletenessChecker.php
@@ -0,0 +1,47 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Service;
+
+use App\BusProNet\Model\PersonalData;
+use Symfony\Component\Validator\Validator\ValidatorInterface;
+
+/**
+ * Validates profile completeness for booking requirements.
+ *
+ * Checks whether a user's personal data contains all required fields needed to create
+ * or edit bookings using Symfony's validation system with the 'personal_data' group.
+ * Required fields include name, gender, date of birth, nationality, contact information,
+ * and full address data.
+ */
+class ProfileCompletenessChecker
+{
+    private const VALIDATION_GROUP = 'personal_data';
+
+    public function __construct(
+        private readonly ValidatorInterface $validator,
+    ) {
+    }
+
+    /**
+     * Checks if the personal data contains all required fields for booking operations.
+     *
+     * Validates against the 'personal_data' group which includes:
+     * - firstName and name (personal identification)
+     * - gender and dateOfBirth (personal attributes)
+     * - nationality (booking form requirement)
+     * - email and mobile (communication)
+     * - street, postCode, city, country (applicant address)
+     *
+     * @param PersonalData $personalData The personal data to validate
+     *
+     * @return bool True if all required fields are present and valid, false otherwise
+     */
+    public function isComplete(PersonalData $personalData): bool
+    {
+        $violations = $this->validator->validate($personalData, null, [self::VALIDATION_GROUP]);
+
+        return 0 === $violations->count();
+    }
+}
diff --git a/templates/account/personal_data.html.twig b/templates/account/personal_data.html.twig
index 9cb1357..56b6200 100644
--- a/templates/account/personal_data.html.twig
+++ b/templates/account/personal_data.html.twig
@@ -1,20 +1,27 @@
 {% extends 'layout.html.twig' %}
 
 {% block content %}
+    {% include '_partials/_flashes.html.twig' %}
     <div class="px-4 lg:px-8 py-8 lg:py-16">
         <h1 class="text-white uppercase pb-4">
             Meine<br>Daten
         </h1>
     </div>
+    {% if app.session.get('_profile_completion_redirect') %}
+        <div class="mx-4 lg:mx-8">
+            {% include '_partials/_alert.html.twig' with {
+                level: 'info',
+                messages: ['Bitte vervollständige erst deine Daten, um fortzufahren.']
+            } %}
+        </div>
+    {% endif %}
     <div class="p-4 lg:p-8">
         <div class="divide-y divide-primary-bg/40">
             <div class="grid md:grid-cols-2 gap-x-8 gap-y-4 pb-8">
                 <div class="text-white">
-                    <strong>Name</strong>: {{ personalData.fullName }}
-                    <br>
-                    <strong>Gender</strong>: {{ personalData.gender|map_gender }}
-                    <br>
-                    <strong>Geburtsdatum</strong>: {{ personalData.dateOfBirth|date('d.m.Y') }}
+                    <h2>
+                        {{ personalData.fullName }}
+                    </h2>
                 </div>
                 <div id="newsletter">
                     <p class="pb-4 text-white">
@@ -32,24 +39,31 @@
                 </div>
             </div>
             <div class="pt-8">
-                <h2 class="text-white uppercase text-xl">
-                    Kontaktdaten
-                </h2>
-                {% include '_partials/_flashes.html.twig' %}
                 {{ form_start(personalDataForm) }}
                 <div class="grid md:grid-cols-2 gap-x-8 gap-y-4 pb-4">
                     <div>
+                        <h3 class="text-white">
+                            Persönliches
+                        </h3>
+                        {{ form_row(personalDataForm.gender, { 'label_attr': { 'class': 'text-white' } }) }}
+                        {{ form_row(personalDataForm.dateOfBirth, { 'label_attr': { 'class': 'text-white' } }) }}
+                        {{ form_row(personalDataForm.nationality, { 'label_attr': { 'class': 'text-white' } }) }}
+                        <h3 class="text-white">
+                            Kontakt
+                        </h3>
+                        {{ form_row(personalDataForm.email, { 'label_attr': { 'class': 'text-white' } }) }}
+                        {{ form_row(personalDataForm.mobile, { 'label_attr': { 'class': 'text-white' } }) }}
+                        {{ form_row(personalDataForm.phone, { 'label_attr': { 'class': 'text-white' } }) }}
+                    </div>
+                    <div>
+                        <h3 class="text-white">
+                            Anschrift
+                        </h3>
                         {{ form_row(personalDataForm.street, { 'label_attr': { 'class': 'text-white' } }) }}
                         {{ form_row(personalDataForm.postCode, { 'label_attr': { 'class': 'text-white' } }) }}
                         {{ form_row(personalDataForm.city, { 'label_attr': { 'class': 'text-white' } }) }}
                         {{ form_row(personalDataForm.country, { 'label_attr': { 'class': 'text-white' } }) }}
                     </div>
-                    <div>
-                        {{ form_row(personalDataForm.nationality, { 'label_attr': { 'class': 'text-white' } }) }}
-                        {{ form_row(personalDataForm.email, { 'label_attr': { 'class': 'text-white' } }) }}
-                        {{ form_row(personalDataForm.phone, { 'label_attr': { 'class': 'text-white' } }) }}
-                        {{ form_row(personalDataForm.mobile, { 'label_attr': { 'class': 'text-white' } }) }}
-                    </div>
                 </div>
                 <div class="flex justify-between">
                     <a href="{{ path('app_account') }}" class="button button--secondary">