diff --git a/apps/dav/lib/AppInfo/Application.php b/apps/dav/lib/AppInfo/Application.php
index f4b590a92808c..5c8bdf770df77 100644
--- a/apps/dav/lib/AppInfo/Application.php
+++ b/apps/dav/lib/AppInfo/Application.php
@@ -19,11 +19,13 @@
 use OCA\DAV\CalDAV\Reminder\NotificationProvider\PushProvider;
 use OCA\DAV\CalDAV\Reminder\NotificationProviderManager;
 use OCA\DAV\CalDAV\Reminder\Notifier as NotifierCalDAV;
+use OCA\DAV\CalDAV\TimezoneService;
 use OCA\DAV\Capabilities;
 use OCA\DAV\CardDAV\ContactsManager;
 use OCA\DAV\CardDAV\Notification\Notifier as NotifierCardDAV;
 use OCA\DAV\CardDAV\SyncService;
 use OCA\DAV\ConfigLexicon;
+use OCA\DAV\Db\PropertyMapper;
 use OCA\DAV\Events\AddressBookCreatedEvent;
 use OCA\DAV\Events\AddressBookDeletedEvent;
 use OCA\DAV\Events\AddressBookShareUpdatedEvent;
@@ -83,13 +85,16 @@
 use OCP\Calendar\Events\CalendarObjectRestoredEvent;
 use OCP\Calendar\Events\CalendarObjectUpdatedEvent;
 use OCP\Calendar\IManager as ICalendarManager;
+use OCP\Calendar\ITimezoneService;
 use OCP\Config\BeforePreferenceDeletedEvent;
 use OCP\Config\BeforePreferenceSetEvent;
+use OCP\Config\IUserConfig;
 use OCP\Contacts\IManager as IContactsManager;
 use OCP\DB\Events\AddMissingIndicesEvent;
 use OCP\Federation\Events\TrustedServerRemovedEvent;
 use OCP\Federation\ICloudFederationProviderManager;
 use OCP\Group\Events\GroupDeletedEvent;
+use OCP\IConfig;
 use OCP\IURLGenerator;
 use OCP\IUserSession;
 use OCP\Server;
@@ -233,6 +238,15 @@ public function register(IRegistrationContext $context): void {
 		$context->registerEventListener(DeclarativeSettingsSetValueEvent::class, DavAdminSettingsListener::class);
 
 		$context->registerConfigLexicon(ConfigLexicon::class);
+
+		$context->registerService(ITimezoneService::class, function (ContainerInterface $c) {
+			return new TimezoneService(
+				$c->get(IConfig::class),
+				$c->get(IUserConfig::class),
+				$c->get(PropertyMapper::class),
+				$c->get(ICalendarManager::class),
+			);
+		});
 	}
 
 	public function boot(IBootContext $context): void {
diff --git a/apps/dav/lib/CalDAV/TimezoneService.php b/apps/dav/lib/CalDAV/TimezoneService.php
index 54c4360d08253..2ba9d79f8adf9 100644
--- a/apps/dav/lib/CalDAV/TimezoneService.php
+++ b/apps/dav/lib/CalDAV/TimezoneService.php
@@ -12,6 +12,7 @@
 use OCA\DAV\Db\PropertyMapper;
 use OCP\Calendar\ICalendar;
 use OCP\Calendar\IManager;
+use OCP\Calendar\ITimezoneService;
 use OCP\Config\IUserConfig;
 use OCP\IConfig;
 use Sabre\VObject\Component\VCalendar;
@@ -19,7 +20,7 @@
 use Sabre\VObject\Reader;
 use function array_reduce;
 
-class TimezoneService {
+class TimezoneService implements ITimezoneService {
 
 	public function __construct(
 		private IConfig $config,
diff --git a/lib/composer/composer/autoload_classmap.php b/lib/composer/composer/autoload_classmap.php
index b2008b286ca25..3bcb89a55a68f 100644
--- a/lib/composer/composer/autoload_classmap.php
+++ b/lib/composer/composer/autoload_classmap.php
@@ -230,6 +230,7 @@
     'OCP\\Calendar\\IHandleImipMessage' => $baseDir . '/lib/public/Calendar/IHandleImipMessage.php',
     'OCP\\Calendar\\IManager' => $baseDir . '/lib/public/Calendar/IManager.php',
     'OCP\\Calendar\\IMetadataProvider' => $baseDir . '/lib/public/Calendar/IMetadataProvider.php',
+    'OCP\\Calendar\\ITimezoneService' => $baseDir . '/lib/public/Calendar/ITimezoneService.php',
     'OCP\\Calendar\\Resource\\IBackend' => $baseDir . '/lib/public/Calendar/Resource/IBackend.php',
     'OCP\\Calendar\\Resource\\IManager' => $baseDir . '/lib/public/Calendar/Resource/IManager.php',
     'OCP\\Calendar\\Resource\\IResource' => $baseDir . '/lib/public/Calendar/Resource/IResource.php',
diff --git a/lib/composer/composer/autoload_static.php b/lib/composer/composer/autoload_static.php
index fb4a73103f5b3..891f6747a05de 100644
--- a/lib/composer/composer/autoload_static.php
+++ b/lib/composer/composer/autoload_static.php
@@ -271,6 +271,7 @@ class ComposerStaticInit749170dad3f5e7f9ca158f5a9f04f6a2
         'OCP\\Calendar\\IHandleImipMessage' => __DIR__ . '/../../..' . '/lib/public/Calendar/IHandleImipMessage.php',
         'OCP\\Calendar\\IManager' => __DIR__ . '/../../..' . '/lib/public/Calendar/IManager.php',
         'OCP\\Calendar\\IMetadataProvider' => __DIR__ . '/../../..' . '/lib/public/Calendar/IMetadataProvider.php',
+        'OCP\\Calendar\\ITimezoneService' => __DIR__ . '/../../..' . '/lib/public/Calendar/ITimezoneService.php',
         'OCP\\Calendar\\Resource\\IBackend' => __DIR__ . '/../../..' . '/lib/public/Calendar/Resource/IBackend.php',
         'OCP\\Calendar\\Resource\\IManager' => __DIR__ . '/../../..' . '/lib/public/Calendar/Resource/IManager.php',
         'OCP\\Calendar\\Resource\\IResource' => __DIR__ . '/../../..' . '/lib/public/Calendar/Resource/IResource.php',
diff --git a/lib/public/Calendar/ITimezoneService.php b/lib/public/Calendar/ITimezoneService.php
new file mode 100644
index 0000000000000..7df94c2758420
--- /dev/null
+++ b/lib/public/Calendar/ITimezoneService.php
@@ -0,0 +1,21 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCP\Calendar;
+
+/**
+ * The timezone service can be used to conveniently get a user's timezone string
+ *
+ * @since 34.0.0
+ */
+interface ITimezoneService {
+	public function getUserTimezone(string $userId): ?string;
+
+	public function getDefaultTimezone(): string;
+}