diff --git a/src/app/sessions/[id]/page.tsx b/src/app/sessions/[id]/page.tsx
index a14b905..194990b 100644
--- a/src/app/sessions/[id]/page.tsx
+++ b/src/app/sessions/[id]/page.tsx
@@ -6,6 +6,7 @@ import { ChevronLeft, Users, Calendar, GlassWater, Plus, Trash2, Loader2, Sparkl
 import Link from 'next/link';
 import AvatarStack from '@/components/AvatarStack';
 import { deleteSession } from '@/services/delete-session';
+import { closeSession } from '@/services/close-session';
 import { useSession } from '@/context/SessionContext';
 import { useParams, useRouter } from 'next/navigation';
 import { useI18n } from '@/i18n/I18nContext';
@@ -28,6 +29,7 @@ interface Session {
     id: string;
     name: string;
     scheduled_at: string;
+    ended_at?: string;
 }
 
 interface SessionTasting {
@@ -62,6 +64,7 @@ export default function SessionDetailPage() {
     const { activeSession, setActiveSession } = useSession();
     const [isAddingParticipant, setIsAddingParticipant] = useState(false);
     const [isDeleting, setIsDeleting] = useState(false);
+    const [isClosing, setIsClosing] = useState(false);
 
     useEffect(() => {
         fetchSessionData();
@@ -148,6 +151,23 @@ export default function SessionDetailPage() {
         }
     };
 
+    const handleCloseSession = async () => {
+        if (!confirm('Möchtest du diese Session wirklich abschließen?')) return;
+
+        setIsClosing(true);
+        const result = await closeSession(id as string);
+
+        if (result.success) {
+            if (activeSession?.id === id) {
+                setActiveSession(null);
+            }
+            fetchSessionData();
+        } else {
+            alert(result.error);
+        }
+        setIsClosing(false);
+    };
+
     const handleDeleteSession = async () => {
         if (!confirm('Möchtest du diese Session wirklich löschen? Alle Verknüpfungen gehen verloren.')) return;
 
@@ -230,9 +250,14 @@ export default function SessionDetailPage() {
                             )}
 
                             <div className="space-y-2">
-                                <div className="flex items-center gap-2 text-amber-600 font-black uppercase text-[10px] tracking-widest">
-                                    <Sparkles size={14} />
-                                    Tasting Session
+                                <div className="flex items-center gap-2">
+                                    <div className="flex items-center gap-2 text-amber-600 font-black uppercase text-[10px] tracking-widest">
+                                        <Sparkles size={14} />
+                                        Tasting Session
+                                    </div>
+                                    {session.ended_at && (
+                                        <span className="bg-zinc-100 dark:bg-zinc-800 text-zinc-500 text-[8px] font-black px-2 py-0.5 rounded-md uppercase tracking-widest border border-zinc-200 dark:border-zinc-700">Abgeschlossen</span>
+                                    )}
                                 </div>
                                 <h1 className="text-4xl md:text-5xl font-black text-zinc-900 dark:text-white tracking-tighter">
                                     {session.name}
@@ -259,22 +284,25 @@ export default function SessionDetailPage() {
                         </div>
 
                         <div className="flex gap-2">
-                            {activeSession?.id !== session.id ? (
-                                <button
-                                    onClick={() => setActiveSession({ id: session.id, name: session.name })}
-                                    className="px-6 py-3 bg-amber-600 hover:bg-amber-700 text-white rounded-2xl text-sm font-black uppercase tracking-widest flex items-center gap-2 transition-all shadow-xl shadow-amber-600/20"
-                                >
-                                    <Play size={18} fill="currentColor" />
-                                    Session Starten
-                                </button>
-                            ) : (
-                                <button
-                                    onClick={() => setActiveSession(null)}
-                                    className="px-6 py-3 bg-zinc-900 dark:bg-zinc-100 text-white dark:text-zinc-900 rounded-2xl text-sm font-black uppercase tracking-widest flex items-center gap-2 border border-zinc-200 dark:border-zinc-800 hover:bg-red-600 hover:text-white dark:hover:bg-red-600 dark:hover:text-white transition-all group"
-                                >
-                                    <Square size={18} className="text-red-500 group-hover:text-white transition-colors" fill="currentColor" />
-                                    Session Stoppen
-                                </button>
+                            {!session.ended_at && (
+                                activeSession?.id !== session.id ? (
+                                    <button
+                                        onClick={() => setActiveSession({ id: session.id, name: session.name })}
+                                        className="px-6 py-3 bg-amber-600 hover:bg-amber-700 text-white rounded-2xl text-sm font-black uppercase tracking-widest flex items-center gap-2 transition-all shadow-xl shadow-amber-600/20"
+                                    >
+                                        <Play size={18} fill="currentColor" />
+                                        Starten
+                                    </button>
+                                ) : (
+                                    <button
+                                        onClick={handleCloseSession}
+                                        disabled={isClosing}
+                                        className="px-6 py-3 bg-zinc-900 dark:bg-zinc-100 text-white dark:text-zinc-900 rounded-2xl text-sm font-black uppercase tracking-widest flex items-center gap-2 border border-zinc-200 dark:border-zinc-800 hover:bg-red-600 hover:text-white dark:hover:bg-red-600 dark:hover:text-white transition-all group"
+                                    >
+                                        {isClosing ? <Loader2 size={18} className="animate-spin" /> : <Square size={18} className="text-red-500 group-hover:text-white transition-colors" fill="currentColor" />}
+                                        Beenden
+                                    </button>
+                                )
                             )}
 
                             <button
diff --git a/src/components/SessionList.tsx b/src/components/SessionList.tsx
index 8f32dc1..83d87ac 100644
--- a/src/components/SessionList.tsx
+++ b/src/components/SessionList.tsx
@@ -13,6 +13,7 @@ interface Session {
     id: string;
     name: string;
     scheduled_at: string;
+    ended_at?: string;
     participant_count?: number;
     whisky_count?: number;
     participants?: string[];
@@ -195,8 +196,11 @@ export default function SessionList() {
                                         }`}
                                 >
                                     <Link href={`/sessions/${session.id}`} className="flex-1 space-y-1 min-w-0">
-                                        <div className={`font-bold truncate ${activeSession?.id === session.id ? 'text-white' : 'text-zinc-800 dark:text-zinc-100'}`}>
+                                        <div className={`font-bold truncate flex items-center gap-2 ${activeSession?.id === session.id ? 'text-white' : 'text-zinc-800 dark:text-zinc-100'}`}>
                                             {session.name}
+                                            {session.ended_at && (
+                                                <span className={`text-[8px] font-black uppercase px-1.5 py-0.5 rounded border ${activeSession?.id === session.id ? 'bg-white/20 border-white/30 text-white' : 'bg-zinc-100 dark:bg-zinc-800 border-zinc-200 dark:border-zinc-700 text-zinc-400'}`}>Closed</span>
+                                            )}
                                         </div>
                                         <div className={`flex items-center gap-4 text-[10px] font-black uppercase tracking-widest ${activeSession?.id === session.id ? 'text-white/80' : 'text-zinc-400'}`}>
                                             <span className="flex items-center gap-1">
@@ -218,13 +222,19 @@ export default function SessionList() {
                                     </Link>
                                     <div className="flex items-center gap-2">
                                         {activeSession?.id !== session.id ? (
-                                            <button
-                                                onClick={() => setActiveSession({ id: session.id, name: session.name })}
-                                                className="p-2 bg-white dark:bg-zinc-700 text-amber-600 rounded-xl shadow-sm border border-zinc-200 dark:border-zinc-600 hover:scale-110 transition-transform"
-                                                title="Start Session"
-                                            >
-                                                <GlassWater size={18} />
-                                            </button>
+                                            !session.ended_at ? (
+                                                <button
+                                                    onClick={() => setActiveSession({ id: session.id, name: session.name })}
+                                                    className="p-2 bg-white dark:bg-zinc-700 text-amber-600 rounded-xl shadow-sm border border-zinc-200 dark:border-zinc-600 hover:scale-110 transition-transform"
+                                                    title="Start Session"
+                                                >
+                                                    <GlassWater size={18} />
+                                                </button>
+                                            ) : (
+                                                <div className="p-2 bg-zinc-100 dark:bg-zinc-800/50 text-zinc-400 rounded-xl border border-zinc-200 dark:border-zinc-700 opacity-50">
+                                                    <Check size={18} />
+                                                </div>
+                                            )
                                         ) : (
                                             <div className="p-2 bg-white/20 text-white rounded-xl">
                                                 <Check size={18} />
diff --git a/src/services/close-session.ts b/src/services/close-session.ts
new file mode 100644
index 0000000..9b8a694
--- /dev/null
+++ b/src/services/close-session.ts
@@ -0,0 +1,30 @@
+'use server';
+
+import { createClient } from '@/lib/supabase/server';
+import { revalidatePath } from 'next/cache';
+
+export async function closeSession(sessionId: string) {
+    const supabase = await createClient();
+
+    try {
+        const { error } = await supabase
+            .from('tasting_sessions')
+            .update({
+                ended_at: new Date().toISOString(),
+            })
+            .eq('id', sessionId);
+
+        if (error) throw error;
+
+        revalidatePath(`/sessions/${sessionId}`);
+        revalidatePath('/');
+
+        return { success: true };
+    } catch (error) {
+        console.error('Close Session Error:', error);
+        return {
+            success: false,
+            error: error instanceof Error ? error.message : 'Fehler beim Beenden der Session',
+        };
+    }
+}