diff --git a/pcbnew/plugins/altium/altium_parser_pcb.h b/pcbnew/plugins/altium/altium_parser_pcb.h
index 53f39db5cc..3ef95fa935 100644
--- a/pcbnew/plugins/altium/altium_parser_pcb.h
+++ b/pcbnew/plugins/altium/altium_parser_pcb.h
@@ -2,7 +2,7 @@
  * This program source code file is part of KiCad, a free EDA CAD application.
  *
  * Copyright (C) 2020 Thomas Pointhuber <thomas.pointhuber@gmx.at>
- * Copyright (C) 2021-2023 KiCad Developers, see AUTHORS.txt for contributors.
+ * Copyright (C) 2021-2024 KiCad Developers, see AUTHORS.txt for contributors.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -42,6 +42,9 @@ const uint16_t ALTIUM_COMPONENT_NONE = std::numeric_limits<uint16_t>::max();
 // this constant specifies a item which does not define a polygon
 const uint16_t ALTIUM_POLYGON_NONE = std::numeric_limits<uint16_t>::max();
 
+// 65534 seems to be belonging to board outline
+const uint16_t ALTIUM_POLYGON_BOARD = std::numeric_limits<uint16_t>::max() - 1;
+
 
 enum class ALTIUM_UNIT
 {
diff --git a/pcbnew/plugins/altium/altium_pcb.cpp b/pcbnew/plugins/altium/altium_pcb.cpp
index b3adb4f3f8..c4bf35af1a 100644
--- a/pcbnew/plugins/altium/altium_pcb.cpp
+++ b/pcbnew/plugins/altium/altium_pcb.cpp
@@ -2457,8 +2457,12 @@ void ALTIUM_PCB::ConvertArcs6ToPcbShape( const AARC6& aElem, PCB_SHAPE* aShape )
 
 void ALTIUM_PCB::ConvertArcs6ToBoardItem( const AARC6& aElem, const int aPrimitiveIndex )
 {
-    if( aElem.is_polygonoutline || aElem.subpolyindex != ALTIUM_POLYGON_NONE )
+    if( aElem.is_polygonoutline
+        || ( aElem.subpolyindex != ALTIUM_POLYGON_NONE
+             && aElem.subpolyindex != ALTIUM_POLYGON_BOARD ) )
+    {
         return;
+    }
 
     if( aElem.is_keepout || aElem.layer == ALTIUM_LAYER::KEEP_OUT_LAYER
         || IsAltiumLayerAPlane( aElem.layer ) )
@@ -3156,8 +3160,12 @@ void ALTIUM_PCB::ParseTracks6Data( const ALTIUM_COMPOUND_FILE&     aAltiumPcbFil
 
 void ALTIUM_PCB::ConvertTracks6ToBoardItem( const ATRACK6& aElem, const int aPrimitiveIndex )
 {
-    if( aElem.is_polygonoutline || aElem.subpolyindex != ALTIUM_POLYGON_NONE )
+    if( aElem.is_polygonoutline
+        || ( aElem.subpolyindex != ALTIUM_POLYGON_NONE
+             && aElem.subpolyindex != ALTIUM_POLYGON_BOARD ) )
+    {
         return;
+    }
 
     if( aElem.is_keepout || aElem.layer == ALTIUM_LAYER::KEEP_OUT_LAYER
         || IsAltiumLayerAPlane( aElem.layer ) )