diff --git a/mdal/frmts/mdal_flo2d.cpp b/mdal/frmts/mdal_flo2d.cpp
index b31a29f9..8eb6838a 100644
--- a/mdal/frmts/mdal_flo2d.cpp
+++ b/mdal/frmts/mdal_flo2d.cpp
@@ -996,7 +996,7 @@ MDAL::DriverFlo2D::DriverFlo2D()
   : Driver(
       "FLO2D",
       "Flo2D",
-      "*.nc;;*.DAT",
+      "*.nc;;*.DAT;;*.OUT",
       Capability::ReadMesh | Capability::ReadDatasets | Capability::WriteDatasetsOnFaces )
 {