diff --git a/backend/src/main/java/com/alttd/altitudeweb/controllers/event/EventController.java b/backend/src/main/java/com/alttd/altitudeweb/controllers/event/EventController.java
index 6b4057c..4976882 100644
--- a/backend/src/main/java/com/alttd/altitudeweb/controllers/event/EventController.java
+++ b/backend/src/main/java/com/alttd/altitudeweb/controllers/event/EventController.java
@@ -1,10 +1,13 @@
 package com.alttd.altitudeweb.controllers.event;
 
 import com.alttd.altitudeweb.controllers.chat.ChatMessageMapper;
+import com.alttd.altitudeweb.database.Databases;
+import com.alttd.altitudeweb.database.chat.ChatLogMapper;
 import com.alttd.altitudeweb.model.PermissionClaimDto;
 import com.alttd.altitudeweb.services.chat.ChatService;
 import com.alttd.altitudeweb.services.chat.event_publisher.EventPublisher;
 import com.alttd.altitudeweb.services.chat.event_publisher.EventUser;
+import com.alttd.altitudeweb.setup.Connection;
 import jakarta.servlet.http.HttpServletResponse;
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
@@ -21,7 +24,9 @@ import org.springframework.web.servlet.mvc.method.annotation.SseEmitter;
 import java.time.Duration;
 import java.time.Instant;
 import java.util.List;
+import java.util.Optional;
 import java.util.UUID;
+import java.util.concurrent.CompletableFuture;
 import java.util.stream.Collectors;
 
 @RequiredArgsConstructor
@@ -62,7 +67,29 @@ public class EventController {
                 .map(ChatMessageMapper::toJson)
                 .collect(Collectors.joining(",", "[", "]"));
 
-        return eventPublisher.subscribe(new EventUser(subject, authorities), json);
+        Integer partyId = getPartyId(subject);
+        return eventPublisher.subscribe(new EventUser(subject, authorities, partyId), json);
+    }
+
+    private Integer getPartyId(UUID subject) {
+        CompletableFuture<Integer> partyIdFuture = new CompletableFuture<>();
+
+        Connection.getConnection(Databases.CHAT)
+                .runQuery(sqlSession -> {
+                    log.debug("Loading party id for uuid {}", subject);
+                    try {
+                        Integer partyId = sqlSession.getMapper(ChatLogMapper.class)
+                                .getPartyId(subject.toString())
+                                .orElse(null);
+
+                        partyIdFuture.complete(partyId);
+                    } catch (Exception e) {
+                        log.error("Failed to load party id", e);
+                        partyIdFuture.complete(null);
+                    }
+                });
+
+        return partyIdFuture.join();
     }
 
     private static boolean doesNotHavePermission(List<String> authorities) {
diff --git a/backend/src/main/java/com/alttd/altitudeweb/services/chat/ChatService.java b/backend/src/main/java/com/alttd/altitudeweb/services/chat/ChatService.java
index 51a397b..a8dcb9f 100644
--- a/backend/src/main/java/com/alttd/altitudeweb/services/chat/ChatService.java
+++ b/backend/src/main/java/com/alttd/altitudeweb/services/chat/ChatService.java
@@ -113,9 +113,11 @@ public class ChatService {
         return switch (chatMessage.getType()) {
             case PUBLIC, GLOBAL -> true;
             case PARTY -> {
-                // TODO [Stijn] [2026-07-19]: Check if user is in party
-                // if (isInParty(eventUser, chatMessage.getChannel())) return true;
-                yield false;
+                Integer partyId = eventUser.partyId();
+                if (partyId == null) {
+                    yield false;
+                }
+                yield chatMessage.getChannel().equals(String.valueOf(partyId));
             }
             case MSG -> {
                 if (eventUser.uuid().equals(chatMessage.getUuid())) {
diff --git a/backend/src/main/java/com/alttd/altitudeweb/services/chat/event_publisher/EventUser.java b/backend/src/main/java/com/alttd/altitudeweb/services/chat/event_publisher/EventUser.java
index c713063..0062dc1 100644
--- a/backend/src/main/java/com/alttd/altitudeweb/services/chat/event_publisher/EventUser.java
+++ b/backend/src/main/java/com/alttd/altitudeweb/services/chat/event_publisher/EventUser.java
@@ -6,7 +6,7 @@ import java.util.List;
 import java.util.Objects;
 import java.util.UUID;
 
-public record EventUser(UUID uuid, List<String> authorities) {
+public record EventUser(UUID uuid, List<String> authorities, Integer partyId) {
 
     public boolean hasPermission(PermissionClaimDto permission) {
         return authorities.contains(permission.getValue());
diff --git a/database/src/main/java/com/alttd/altitudeweb/database/chat/ChatLogMapper.java b/database/src/main/java/com/alttd/altitudeweb/database/chat/ChatLogMapper.java
index 634ca33..e4b49e7 100644
--- a/database/src/main/java/com/alttd/altitudeweb/database/chat/ChatLogMapper.java
+++ b/database/src/main/java/com/alttd/altitudeweb/database/chat/ChatLogMapper.java
@@ -4,6 +4,7 @@ import org.apache.ibatis.annotations.Param;
 import org.apache.ibatis.annotations.Select;
 
 import java.util.List;
+import java.util.Optional;
 
 public interface ChatLogMapper {
 
@@ -15,4 +16,10 @@ public interface ChatLogMapper {
             """)
     List<ChatLogDao> getChatLogs(@Param("since") long since);
 
+    @Select("""
+            SELECT party_id FROM chat_users
+            WHERE uuid = #{uuid}
+            """)
+    Optional<Integer> getPartyId(@Param("uuid") String uuid);
+
 }