diff --git a/server/gameserver/mapinstance.cc b/server/gameserver/mapinstance.cc
index a370eba5..5b2d4362 100644
--- a/server/gameserver/mapinstance.cc
+++ b/server/gameserver/mapinstance.cc
@@ -18,6 +18,7 @@
 #include "mt/MetaMgr.h"
 #include "mt/Param.h"
 #include "mt/Map.h"
+#include "mt/MapArea.h"
 
 #include "roommgr.h"
 
@@ -608,4 +609,25 @@ void MapInstance::MarkMapAreaPolys()
     if (!tile) {
         abort();
     }
+    for (int i = 0; i < tile->header->polyCount; ++i) {
+        dtPoly* poly = &tile->polys[i];
+        const mt::MapArea* last_area_meta = nullptr;
+        if ((poly->flags & SAMPLE_POLYFLAGS_SWIM) == SAMPLE_POLYFLAGS_SWIM) {
+            for (int ii = 0; ii < poly->vertCount; ++ii) {
+                const float* vc = &tile->verts[poly->verts[ii]*3];
+                const mt::MapArea* area_meta = mt::MapArea::GetAreaByPoint
+                    (map_meta_->map_id(),
+                     vc[0] * GetMapMeta()->scale(),
+                     vc[1],
+                     vc[2] * GetMapMeta()->scale());
+                if (!area_meta) {
+                    abort();
+                }
+                if (last_area_meta && last_area_meta != area_meta) {
+                    abort();
+                }
+                last_area_meta = area_meta;
+            }
+        }
+    }
 }
diff --git a/server/gameserver/mt/MapArea.cc b/server/gameserver/mt/MapArea.cc
index f74b834b..bc8d7e6e 100644
--- a/server/gameserver/mt/MapArea.cc
+++ b/server/gameserver/mt/MapArea.cc
@@ -18,13 +18,34 @@ namespace mt
         {
             std::vector<std::string> strings;
             a8::Split(area_center(), strings, ':');
+            if (strings.size() != 2) {
+                abort();
+            }
+            center_ = glm::vec2(a8::XValue(strings[0]).GetDouble(), a8::XValue(strings[1]).GetDouble());
         }
     }
 
-    std::vector<const mt::MapArea*>* MapArea::GetAreas(int map_id)
+    const mt::MapArea* MapArea::GetAreaByPoint(int map_id, float x, float y, float z)
     {
         auto itr = map_areas.find(map_id);
-        return itr != map_areas.end() ? &itr->second : nullptr;
+        if (itr != map_areas.end()) {
+            for (auto area_meta : itr->second) {
+                if (x < area_meta->center_.x - area_meta->area_width() / 2) {
+                    break;
+                }
+                if (x > area_meta->center_.x + area_meta->area_width() / 2) {
+                    break;
+                }
+                if (y < area_meta->center_.y - area_meta->area_height() / 2) {
+                    break;
+                }
+                if (y > area_meta->center_.y + area_meta->area_height() / 2) {
+                    break;
+                }
+                return area_meta;
+            }
+        }
+        return nullptr;
     }
 
 }
diff --git a/server/gameserver/mt/MapArea.h b/server/gameserver/mt/MapArea.h
index 61a87ca3..33be7b50 100644
--- a/server/gameserver/mt/MapArea.h
+++ b/server/gameserver/mt/MapArea.h
@@ -12,9 +12,8 @@ namespace mt
     public:
 
         void Init1();
-        const glm::vec2 GetCenter() { return center_; };
 
-        static std::vector<const mt::MapArea*>* GetAreas(int map_id);
+        static const mt::MapArea* GetAreaByPoint(int map_id, float x, float y, float z);
 
     private:
         glm::vec2 center_ = glm::vec2(0.0f, 0.0f);