diff --git a/modules/tournament/src/main/scala/de/nowchess/tournament/resource/TournamentResource.scala b/modules/tournament/src/main/scala/de/nowchess/tournament/resource/TournamentResource.scala
index 67884bf..2b4e1c2 100644
--- a/modules/tournament/src/main/scala/de/nowchess/tournament/resource/TournamentResource.scala
+++ b/modules/tournament/src/main/scala/de/nowchess/tournament/resource/TournamentResource.scala
@@ -119,6 +119,16 @@ class TournamentResource:
         case Some(nativeId) => tournamentService.setNativeTournamentId(t.id, nativeId)
         case None           => log.warnf("Failed to publish tournament %s to native server %s", t.id, nativeServerUrl)
 
+  // Mirror a bot join onto the native twin so it surfaces in the UI, which reads participant and
+  // standings fields from the native server (see nativeOverlay).
+  private def joinNativeTwin(id: String, botName: String): Unit =
+    if nativeServerUrl.nonEmpty then
+      tournamentService.get(id).flatMap(nativeIdFor).foreach { nativeId =>
+        if externalClient.joinNativeAsBot(nativeServerUrl, nativeId, botName) then
+          log.infof("Joined bot %s on native twin %s of tournament %s", botName, nativeId, id)
+        else log.warnf("Failed to join bot %s on native twin %s of tournament %s", botName, nativeId, id)
+      }
+
   // Resolve the native-server twin of a local tournament. Backfills the stored id by matching
   // fullName against the native list for tournaments created before the id was captured.
   private def nativeIdFor(t: de.nowchess.tournament.domain.Tournament): Option[String] =
@@ -250,7 +260,14 @@ class TournamentResource:
           val botId   = Option(jwt.getSubject).getOrElse("")
           val botName = Option(jwt.getClaim[AnyRef]("name")).map(_.toString).getOrElse(botId)
           tournamentService.join(id, botId, botName) match
-            case Right(_) => Response.ok(OkDto()).build()
+            case Right(_) =>
+              joinNativeTwin(id, botName)
+              Response.ok(OkDto()).build()
+            // Already in the NowChess participant list but possibly never mirrored onto the native
+            // twin (where the UI reads participants from) — make the native join idempotent.
+            case Left(TournamentError.AlreadyJoined) =>
+              joinNativeTwin(id, botName)
+              Response.ok(OkDto()).build()
             case Left(error) =>
               error match
                 case TournamentError.NotFound(_) =>
diff --git a/modules/tournament/src/main/scala/de/nowchess/tournament/service/ExternalTournamentClient.scala b/modules/tournament/src/main/scala/de/nowchess/tournament/service/ExternalTournamentClient.scala
index 7e81c19..dd8d710 100644
--- a/modules/tournament/src/main/scala/de/nowchess/tournament/service/ExternalTournamentClient.scala
+++ b/modules/tournament/src/main/scala/de/nowchess/tournament/service/ExternalTournamentClient.scala
@@ -60,9 +60,12 @@ class ExternalTournamentClient:
     }
 
   private def registerDirector(serverUrl: String, name: String): Option[String] =
+    registerAccount(serverUrl, name, isBot = false)
+
+  private def registerAccount(serverUrl: String, name: String, isBot: Boolean): Option[String] =
     Try {
       val client = buildClient()
-      val body   = s"""{"name":"${name.replace("\"", "\\\"")}","isBot":false}"""
+      val body   = s"""{"name":"${name.replace("\"", "\\\"")}","isBot":$isBot}"""
       val response = client
         .target(s"$serverUrl/api/auth/register")
         .request(MediaType.APPLICATION_JSON)
@@ -76,6 +79,24 @@ class ExternalTournamentClient:
         client.close()
     }.getOrElse(None)
 
+  // The tournament server holds only the director token, which cannot join as a bot. Register the
+  // bot on the native server by name to mint a bot token, then join the native twin as that bot.
+  def joinNativeAsBot(serverUrl: String, tournamentId: String, botName: String): Boolean =
+    registerAccount(serverUrl, botName, isBot = true).exists { token =>
+      Try {
+        val client = buildClient()
+        val response = client
+          .target(s"$serverUrl/api/tournament/$tournamentId/join")
+          .request(MediaType.APPLICATION_JSON)
+          .header("Authorization", s"Bearer $token")
+          .post(Entity.json(""))
+        try response.getStatus / 100 == 2 || response.getStatus == 409
+        finally
+          response.close()
+          client.close()
+      }.getOrElse(false)
+    }
+
   private def createNative(serverUrl: String, token: String, form: String): Option[String] =
     Try {
       val client = buildClient()