diff --git a/src/main/java/com/garbagemule/MobArena/commands/user/JoinCommand.java b/src/main/java/com/garbagemule/MobArena/commands/user/JoinCommand.java
index 6dfec9b..2c9ae5c 100644
--- a/src/main/java/com/garbagemule/MobArena/commands/user/JoinCommand.java
+++ b/src/main/java/com/garbagemule/MobArena/commands/user/JoinCommand.java
@@ -30,6 +30,18 @@ public class JoinCommand implements Command
         Player p    = Commands.unwrap(sender);
         String arg1 = (args.length > 0 ? args[0] : null);
         
+        // If the player is currently in an arena, leave it first
+        Arena current = am.getArenaWithPlayer(p);
+        if (current != null) {
+            if (current.inArena(p) || current.inLobby(p)) {
+                current.getMessenger().tell(p, Msg.JOIN_ALREADY_PLAYING);
+                return true;
+            }
+            if (!current.playerLeave(p)) {
+                return true;
+            }
+        }
+
         // Run some rough sanity checks, and grab the arena to join.
         Arena toArena = Commands.getArenaToJoinOrSpec(am, p, arg1);
         if (toArena == null || !canJoin(p, toArena)) {
@@ -58,11 +70,6 @@ public class JoinCommand implements Command
             plugin.getGlobalMessenger().tell(player, Msg.JOIN_ALREADY_PLAYING);
             return false;
         }
-        Arena current = am.getArenaWithPlayer(player);
-        if (current != null) {
-            current.getMessenger().tell(player, Msg.JOIN_ALREADY_PLAYING);
-            return false;
-        }
         return arena.canJoin(player);
     }
 
diff --git a/src/main/java/com/garbagemule/MobArena/signs/InvokesSignAction.java b/src/main/java/com/garbagemule/MobArena/signs/InvokesSignAction.java
index e6c89c5..d564362 100644
--- a/src/main/java/com/garbagemule/MobArena/signs/InvokesSignAction.java
+++ b/src/main/java/com/garbagemule/MobArena/signs/InvokesSignAction.java
@@ -20,6 +20,16 @@ class InvokesSignAction {
 
     void invoke(ArenaSign sign, Player player) {
         if (sign.type.equals("join")) {
+            Arena current = arenaMaster.getArenaWithPlayer(player);
+            if (current != null) {
+                if (current.inArena(player) || current.inLobby(player)) {
+                    current.getMessenger().tell(player, Msg.JOIN_ALREADY_PLAYING);
+                    return;
+                }
+                if (!current.playerLeave(player)) {
+                    return;
+                }
+            }
             withArena(sign, player, arena -> {
                 if (arena.canJoin(player)) {
                     // Join message is sent in playerJoin