diff --git a/tests/regression_tests/unstructured_mesh/inputs_true0.dat b/tests/regression_tests/unstructured_mesh/inputs_true0.dat
index e5f7fd6132..7411e9b940 100644
--- a/tests/regression_tests/unstructured_mesh/inputs_true0.dat
+++ b/tests/regression_tests/unstructured_mesh/inputs_true0.dat
@@ -70,7 +70,7 @@
     <upper_right>10.0 10.0 10.0</upper_right>
   </mesh>
   <mesh id="2" library="libmesh" type="unstructured">
-    <filename>test_mesh_tets_w_holes.exo</filename>
+    <filename>test_mesh_tets_w_holes.e</filename>
   </mesh>
   <filter id="1" type="mesh">
     <bins>1</bins>
diff --git a/tests/regression_tests/unstructured_mesh/inputs_true1.dat b/tests/regression_tests/unstructured_mesh/inputs_true1.dat
index 58e2ee468e..e85aab1193 100644
--- a/tests/regression_tests/unstructured_mesh/inputs_true1.dat
+++ b/tests/regression_tests/unstructured_mesh/inputs_true1.dat
@@ -70,7 +70,7 @@
     <upper_right>10.0 10.0 10.0</upper_right>
   </mesh>
   <mesh id="2" library="libmesh" type="unstructured">
-    <filename>test_mesh_tets.exo</filename>
+    <filename>test_mesh_tets.e</filename>
   </mesh>
   <filter id="1" type="mesh">
     <bins>1</bins>
diff --git a/tests/regression_tests/unstructured_mesh/inputs_true10.dat b/tests/regression_tests/unstructured_mesh/inputs_true10.dat
index 0d41154b33..628e5e7bcc 100644
--- a/tests/regression_tests/unstructured_mesh/inputs_true10.dat
+++ b/tests/regression_tests/unstructured_mesh/inputs_true10.dat
@@ -70,7 +70,7 @@
     <upper_right>10.0 10.0 10.0</upper_right>
   </mesh>
   <mesh id="2" library="moab" type="unstructured">
-    <filename>test_mesh_tets_w_holes.exo</filename>
+    <filename>test_mesh_tets_w_holes.e</filename>
   </mesh>
   <filter id="1" type="mesh">
     <bins>1</bins>
diff --git a/tests/regression_tests/unstructured_mesh/inputs_true11.dat b/tests/regression_tests/unstructured_mesh/inputs_true11.dat
index cbdfd518f8..1c0a579e54 100644
--- a/tests/regression_tests/unstructured_mesh/inputs_true11.dat
+++ b/tests/regression_tests/unstructured_mesh/inputs_true11.dat
@@ -70,7 +70,7 @@
     <upper_right>10.0 10.0 10.0</upper_right>
   </mesh>
   <mesh id="2" library="moab" type="unstructured">
-    <filename>test_mesh_tets.exo</filename>
+    <filename>test_mesh_tets.e</filename>
   </mesh>
   <filter id="1" type="mesh">
     <bins>1</bins>
diff --git a/tests/regression_tests/unstructured_mesh/inputs_true12.dat b/tests/regression_tests/unstructured_mesh/inputs_true12.dat
index 0e726216e0..a75344435f 100644
--- a/tests/regression_tests/unstructured_mesh/inputs_true12.dat
+++ b/tests/regression_tests/unstructured_mesh/inputs_true12.dat
@@ -70,7 +70,7 @@
     <upper_right>10.0 10.0 10.0</upper_right>
   </mesh>
   <mesh id="2" library="moab" type="unstructured">
-    <filename>test_mesh_tets_w_holes.exo</filename>
+    <filename>test_mesh_tets_w_holes.e</filename>
   </mesh>
   <filter id="1" type="mesh">
     <bins>1</bins>
diff --git a/tests/regression_tests/unstructured_mesh/inputs_true13.dat b/tests/regression_tests/unstructured_mesh/inputs_true13.dat
index 897e451008..c62c3c9113 100644
--- a/tests/regression_tests/unstructured_mesh/inputs_true13.dat
+++ b/tests/regression_tests/unstructured_mesh/inputs_true13.dat
@@ -70,7 +70,7 @@
     <upper_right>10.0 10.0 10.0</upper_right>
   </mesh>
   <mesh id="2" library="moab" type="unstructured">
-    <filename>test_mesh_tets.exo</filename>
+    <filename>test_mesh_tets.e</filename>
   </mesh>
   <filter id="1" type="mesh">
     <bins>1</bins>
diff --git a/tests/regression_tests/unstructured_mesh/inputs_true14.dat b/tests/regression_tests/unstructured_mesh/inputs_true14.dat
index 6f965dc7e5..b7ac4c048c 100644
--- a/tests/regression_tests/unstructured_mesh/inputs_true14.dat
+++ b/tests/regression_tests/unstructured_mesh/inputs_true14.dat
@@ -70,7 +70,7 @@
     <upper_right>10.0 10.0 10.0</upper_right>
   </mesh>
   <mesh id="2" library="moab" type="unstructured">
-    <filename>test_mesh_tets_w_holes.exo</filename>
+    <filename>test_mesh_tets_w_holes.e</filename>
   </mesh>
   <filter id="1" type="mesh">
     <bins>1</bins>
diff --git a/tests/regression_tests/unstructured_mesh/inputs_true15.dat b/tests/regression_tests/unstructured_mesh/inputs_true15.dat
index df0a8d0b03..1d96efc7d3 100644
--- a/tests/regression_tests/unstructured_mesh/inputs_true15.dat
+++ b/tests/regression_tests/unstructured_mesh/inputs_true15.dat
@@ -70,7 +70,7 @@
     <upper_right>10.0 10.0 10.0</upper_right>
   </mesh>
   <mesh id="2" library="moab" type="unstructured">
-    <filename>test_mesh_tets.exo</filename>
+    <filename>test_mesh_tets.e</filename>
   </mesh>
   <filter id="1" type="mesh">
     <bins>1</bins>
diff --git a/tests/regression_tests/unstructured_mesh/inputs_true2.dat b/tests/regression_tests/unstructured_mesh/inputs_true2.dat
index 751a8e0b47..a2a2d4a27a 100644
--- a/tests/regression_tests/unstructured_mesh/inputs_true2.dat
+++ b/tests/regression_tests/unstructured_mesh/inputs_true2.dat
@@ -70,7 +70,7 @@
     <upper_right>10.0 10.0 10.0</upper_right>
   </mesh>
   <mesh id="2" library="libmesh" type="unstructured">
-    <filename>test_mesh_tets_w_holes.exo</filename>
+    <filename>test_mesh_tets_w_holes.e</filename>
   </mesh>
   <filter id="1" type="mesh">
     <bins>1</bins>
diff --git a/tests/regression_tests/unstructured_mesh/inputs_true3.dat b/tests/regression_tests/unstructured_mesh/inputs_true3.dat
index bbfbc6402f..c96f902016 100644
--- a/tests/regression_tests/unstructured_mesh/inputs_true3.dat
+++ b/tests/regression_tests/unstructured_mesh/inputs_true3.dat
@@ -70,7 +70,7 @@
     <upper_right>10.0 10.0 10.0</upper_right>
   </mesh>
   <mesh id="2" library="libmesh" type="unstructured">
-    <filename>test_mesh_tets.exo</filename>
+    <filename>test_mesh_tets.e</filename>
   </mesh>
   <filter id="1" type="mesh">
     <bins>1</bins>
diff --git a/tests/regression_tests/unstructured_mesh/inputs_true8.dat b/tests/regression_tests/unstructured_mesh/inputs_true8.dat
index 9d67b8909e..9a7ad57113 100644
--- a/tests/regression_tests/unstructured_mesh/inputs_true8.dat
+++ b/tests/regression_tests/unstructured_mesh/inputs_true8.dat
@@ -70,7 +70,7 @@
     <upper_right>10.0 10.0 10.0</upper_right>
   </mesh>
   <mesh id="2" library="moab" type="unstructured">
-    <filename>test_mesh_tets_w_holes.exo</filename>
+    <filename>test_mesh_tets_w_holes.e</filename>
   </mesh>
   <filter id="1" type="mesh">
     <bins>1</bins>
diff --git a/tests/regression_tests/unstructured_mesh/inputs_true9.dat b/tests/regression_tests/unstructured_mesh/inputs_true9.dat
index f81a476124..8aedad2377 100644
--- a/tests/regression_tests/unstructured_mesh/inputs_true9.dat
+++ b/tests/regression_tests/unstructured_mesh/inputs_true9.dat
@@ -70,7 +70,7 @@
     <upper_right>10.0 10.0 10.0</upper_right>
   </mesh>
   <mesh id="2" library="moab" type="unstructured">
-    <filename>test_mesh_tets.exo</filename>
+    <filename>test_mesh_tets.e</filename>
   </mesh>
   <filter id="1" type="mesh">
     <bins>1</bins>
diff --git a/tests/regression_tests/unstructured_mesh/test.py b/tests/regression_tests/unstructured_mesh/test.py
index 4b09a10de4..c921a78482 100644
--- a/tests/regression_tests/unstructured_mesh/test.py
+++ b/tests/regression_tests/unstructured_mesh/test.py
@@ -198,9 +198,9 @@ def test_unstructured_mesh(test_opts):
     regular_mesh_filter = openmc.MeshFilter(mesh=regular_mesh)
 
     if test_opts['holes']:
-        mesh_filename = "test_mesh_tets_w_holes.exo"
+        mesh_filename = "test_mesh_tets_w_holes.e"
     else:
-        mesh_filename = "test_mesh_tets.exo"
+        mesh_filename = "test_mesh_tets.e"
 
     uscd_mesh = openmc.UnstructuredMesh(mesh_filename, test_opts['library'])
     uscd_filter = openmc.MeshFilter(mesh=uscd_mesh)
diff --git a/tests/regression_tests/unstructured_mesh/test_mesh_tets.e b/tests/regression_tests/unstructured_mesh/test_mesh_tets.e
new file mode 100644
index 0000000000..90e7473603
Binary files /dev/null and b/tests/regression_tests/unstructured_mesh/test_mesh_tets.e differ
diff --git a/tests/regression_tests/unstructured_mesh/test_mesh_tets_w_holes.e b/tests/regression_tests/unstructured_mesh/test_mesh_tets_w_holes.e
new file mode 100644
index 0000000000..3c30a55dc8
Binary files /dev/null and b/tests/regression_tests/unstructured_mesh/test_mesh_tets_w_holes.e differ