diff --git a/src/server/game/Instances/InstanceScript.cpp b/src/server/game/Instances/InstanceScript.cpp
index 68dae4f388..8ead6745c2 100644
--- a/src/server/game/Instances/InstanceScript.cpp
+++ b/src/server/game/Instances/InstanceScript.cpp
@@ -26,6 +26,7 @@
 #include "Group.h"
 #include "Guild.h"
 #include "GuildMgr.h"
+#include "InstancePackets.h"
 #include "LFGMgr.h"
 #include "Log.h"
 #include "Map.h"
@@ -683,9 +684,10 @@ bool InstanceScript::CheckAchievementCriteriaMeet(uint32 criteria_id, Player con
 
 void InstanceScript::SendEncounterUnit(uint32 type, Unit* unit /*= nullptr*/, uint8 param1 /*= 0*/, uint8 param2 /*= 0*/)
 {
-    // size of this packet is at most 15 (usually less)
-    WorldPacket data(SMSG_UPDATE_INSTANCE_ENCOUNTER_UNIT, 15);
-    data << uint32(type);
+    WorldPackets::Instance::UpdateInstanceEncounterUnit packet;
+    packet.Type = type;
+    packet.Param1 = param1;
+    packet.Param2 = param2;
 
     switch (type)
     {
@@ -694,27 +696,14 @@ void InstanceScript::SendEncounterUnit(uint32 type, Unit* unit /*= nullptr*/, ui
         case ENCOUNTER_FRAME_UPDATE_PRIORITY:
             if (!unit)
                 return;
-            data.appendPackGUID(unit->GetGUID());
-            data << uint8(param1);
+
+            packet.Unit = unit->GetGUID();
             break;
-        case ENCOUNTER_FRAME_ADD_TIMER:
-        case ENCOUNTER_FRAME_ENABLE_OBJECTIVE:
-        case ENCOUNTER_FRAME_DISABLE_OBJECTIVE:
-        case ENCOUNTER_FRAME_SET_COMBAT_RES_LIMIT:
-            data << uint8(param1);
-            break;
-        case ENCOUNTER_FRAME_UPDATE_OBJECTIVE:
-            data << uint8(param1);
-            data << uint8(param2);
-            break;
-        case ENCOUNTER_FRAME_UNK7:
-        case ENCOUNTER_FRAME_ADD_COMBAT_RES_LIMIT:
-        case ENCOUNTER_FRAME_RESET_COMBAT_RES_LIMIT:
         default:
             break;
     }
 
-    instance->SendToPlayers(&data);
+    instance->SendToPlayers(packet.Write());
 }
 
 void InstanceScript::UpdateEncounterState(EncounterCreditType type, uint32 creditEntry, Unit* /*source*/)
diff --git a/src/server/game/Maps/Map.cpp b/src/server/game/Maps/Map.cpp
index c33c2836ab..61ba3df83b 100644
--- a/src/server/game/Maps/Map.cpp
+++ b/src/server/game/Maps/Map.cpp
@@ -3595,7 +3595,7 @@ uint32 Map::GetPlayersCountExceptGMs() const
     return count;
 }
 
-void Map::SendToPlayers(WorldPacket* data) const
+void Map::SendToPlayers(WorldPacket const* data) const
 {
     for (MapRefManager::const_iterator itr = m_mapRefManager.begin(); itr != m_mapRefManager.end(); ++itr)
         itr->GetSource()->SendDirectMessage(data);
diff --git a/src/server/game/Maps/Map.h b/src/server/game/Maps/Map.h
index faf0ab6cef..9e6e03f7a6 100644
--- a/src/server/game/Maps/Map.h
+++ b/src/server/game/Maps/Map.h
@@ -536,7 +536,7 @@ class TC_GAME_API Map : public GridRefManager<NGridType>
         void AddWorldObject(WorldObject* obj) { i_worldObjects.insert(obj); }
         void RemoveWorldObject(WorldObject* obj) { i_worldObjects.erase(obj); }
 
-        void SendToPlayers(WorldPacket* data) const;
+        void SendToPlayers(WorldPacket const* data) const;
 
         typedef MapRefManager PlayerList;
         PlayerList const& GetPlayers() const { return m_mapRefManager; }
diff --git a/src/server/game/Server/Packets/InstancePackets.cpp b/src/server/game/Server/Packets/InstancePackets.cpp
index 860e052fd1..3684947132 100644
--- a/src/server/game/Server/Packets/InstancePackets.cpp
+++ b/src/server/game/Server/Packets/InstancePackets.cpp
@@ -16,6 +16,7 @@
  */
 
 #include "InstancePackets.h"
+#include "InstanceScript.h"
 #include "Player.h"
 
 WorldPacket const* WorldPackets::Instance::UpdateLastInstance::Write()
@@ -96,3 +97,36 @@ WorldPacket const* WorldPackets::Instance::RaidGroupOnly::Write()
 
     return &_worldPacket;
 }
+
+WorldPacket const* WorldPackets::Instance::UpdateInstanceEncounterUnit::Write()
+{
+    _worldPacket << uint32(Type);
+
+    switch (Type)
+    {
+        case ENCOUNTER_FRAME_ENGAGE:
+        case ENCOUNTER_FRAME_DISENGAGE:
+        case ENCOUNTER_FRAME_UPDATE_PRIORITY:
+            _worldPacket << Unit.WriteAsPacked();
+            _worldPacket << uint8(Param1);
+            break;
+        case ENCOUNTER_FRAME_ADD_TIMER:
+        case ENCOUNTER_FRAME_ENABLE_OBJECTIVE:
+        case ENCOUNTER_FRAME_DISABLE_OBJECTIVE:
+        case ENCOUNTER_FRAME_SET_COMBAT_RES_LIMIT:
+            _worldPacket << uint8(Param1);
+            break;
+        case ENCOUNTER_FRAME_UPDATE_OBJECTIVE:
+            _worldPacket << uint8(Param1);
+            _worldPacket << uint8(Param2);
+            break;
+        case ENCOUNTER_FRAME_UNK7:
+        case ENCOUNTER_FRAME_ADD_COMBAT_RES_LIMIT:
+        case ENCOUNTER_FRAME_RESET_COMBAT_RES_LIMIT:
+            break;
+        default:
+            break;
+    }
+
+    return &_worldPacket;
+}
diff --git a/src/server/game/Server/Packets/InstancePackets.h b/src/server/game/Server/Packets/InstancePackets.h
index 0a10be20c9..268b8c17ee 100644
--- a/src/server/game/Server/Packets/InstancePackets.h
+++ b/src/server/game/Server/Packets/InstancePackets.h
@@ -116,6 +116,19 @@ namespace WorldPackets
             uint32 Reason = 0;
             int32 Delay = 0;
         };
+
+        class UpdateInstanceEncounterUnit final : public ServerPacket
+        {
+        public:
+            UpdateInstanceEncounterUnit() : ServerPacket(SMSG_UPDATE_INSTANCE_ENCOUNTER_UNIT, 4 + 8 + 1 + 1) { }
+
+            WorldPacket const* Write() override;
+
+            uint32 Type = 0;
+            ObjectGuid Unit;
+            uint8 Param1 = 0;
+            uint8 Param2 = 0;
+        };
     }
 }