diff --git a/meshmode/interop/firedrake/connection.py b/meshmode/interop/firedrake/connection.py
index e0de6fc9fcf3b6c64a9919b89ba979dffb85c8cd..8ce7a4e21f089c313f5c9f0ddbbae501413c4638 100644
--- a/meshmode/interop/firedrake/connection.py
+++ b/meshmode/interop/firedrake/connection.py
@@ -541,7 +541,8 @@ def _compute_cells_near_bdy(mesh, bdy_id):
     # Reduce along each cell: Is a vertex of the cell in boundary nodes?
     cell_is_near_bdy = np.any(np.isin(cell_node_list, boundary_nodes), axis=1)
 
-    return np.nonzero(cell_is_near_bdy)[0].astype(np.int32)
+    from pyop2.datatypes import IntType
+    return np.nonzero(cell_is_near_bdy)[0].astype(IntType)
 
 
 class FromBdyFiredrakeConnection(FiredrakeConnection):
@@ -653,13 +654,14 @@ class ToFiredrakeConnection(FiredrakeConnection):
         fd_unit_nodes = get_finat_element_unit_nodes(fspace.finat_element)
         fd_unit_nodes = fd_ref_cell_to_mm(fd_unit_nodes)
 
-        # To get the meshmode to firedrake node assocation, we need to handle
-        # local vertex reordering and cell reordering.
-        #
         # **_cell_node holds the node nrs in shape *(ncells, nunit_nodes)*
         fd_cell_node = fspace.cell_node_list
         mm_cell_node = el_group.view(np.arange(discr.nnodes))
-        reordering_arr = np.arange(el_group.nnodes, dtype=fd_cell_node.dtype)
+
+        # To get the meshmode to firedrake node assocation, we need to handle
+        # local vertex reordering and cell reordering.
+        from pyop2.datatypes import IntType
+        reordering_arr = np.arange(el_group.nnodes, dtype=IntType)
         for perm, cells in six.iteritems(perm2cells):
             # reordering_arr[i] should be the fd node corresponding to meshmode
             # node i
@@ -679,7 +681,7 @@ class ToFiredrakeConnection(FiredrakeConnection):
             flip_mat = get_simplex_element_flip_matrix(el_group.order,
                                                        fd_unit_nodes,
                                                        np.argsort(perm))
-            flip_mat = np.rint(flip_mat).astype(np.int32)
+            flip_mat = np.rint(flip_mat).astype(IntType)
             fd_permuted_cell_node = np.matmul(fd_cell_node[fd_cell_order[cells]],
                                               flip_mat.T)
             reordering_arr[mm_cell_node[cells]] = fd_permuted_cell_node
diff --git a/meshmode/interop/firedrake/mesh.py b/meshmode/interop/firedrake/mesh.py
index 6e425ba6f27ce171325c096a18061e236837ad26..d2d32e260413a227806deaf88026f6b5ad6d6620 100644
--- a/meshmode/interop/firedrake/mesh.py
+++ b/meshmode/interop/firedrake/mesh.py
@@ -86,13 +86,14 @@ def _get_firedrake_nodal_info(fdrake_mesh_topology, cells_to_use=None):
     # Maps dmplex vert id -> firedrake vert index
     vert_id_dmp_to_fd = top._vertex_numbering.getOffset
 
-    # We will fill in the values as we go
+    # We will fill in the values of vertex indices as we go
     if cells_to_use is None:
         num_cells = top.num_cells()
     else:
         num_cells = np.size(cells_to_use)
+    from pyop2.datatypes import IntType
     vertex_indices = -np.ones((num_cells, top.ufl_cell().num_vertices()),
-                              dtype=np.int32)
+                              dtype=IntType)
     # This will map fd cell ndx (or its new index as dictated by
     #                            *cells_to_use* if *cells_to_use*
     #                            is not *None*)
@@ -146,12 +147,12 @@ def _get_firedrake_nodal_info(fdrake_mesh_topology, cells_to_use=None):
         num_cells = top.num_cells()
     else:
         num_cells = np.size(cells_to_use)
-    neighbors_starts = np.zeros(num_cells + 1, dtype=np.int32)
+    neighbors_starts = np.zeros(num_cells + 1, dtype=IntType)
     for iel in range(len(cell_to_nodal_neighbors)):
         neighbors += cell_to_nodal_neighbors[iel]
         neighbors_starts[iel+1] = len(neighbors)
 
-    neighbors = np.array(neighbors, dtype=np.int32)
+    neighbors = np.array(neighbors, dtype=IntType)
 
     nodal_adjacency = NodalAdjacency(neighbors_starts=neighbors_starts,
                                      neighbors=neighbors)
@@ -268,10 +269,12 @@ def _get_firedrake_facial_adjacency_groups(fdrake_mesh_topology,
                                          int_fac_loc_nr[:, 0]))
     int_neighbor_faces = int_neighbor_faces.astype(Mesh.face_id_dtype)
     # If only using some of the cells
+    from pyop2.datatypes import IntType
     if cells_to_use is not None:
         to_keep = np.isin(int_elements, cells_to_use)
         cells_to_use_inv = dict(zip(cells_to_use,
-                                    np.arange(np.size(cells_to_use))))
+                                    np.arange(np.size(cells_to_use),
+                                              dtype=IntType)))
 
         # Only keep cells that using, and change to new cell index
         int_elements = np.vectorize(cells_to_use_inv.__getitem__)(
@@ -301,8 +304,8 @@ def _get_firedrake_facial_adjacency_groups(fdrake_mesh_topology,
     ext_elements = top.exterior_facets.facet_cell.flatten()
 
     ext_element_faces = np.array([fd_loc_fac_nr_to_mm[fac_nr] for fac_nr in
-                                  top.exterior_facets.local_facet_dat.data])
-    ext_element_faces = ext_element_faces.astype(Mesh.face_id_dtype)
+                                  top.exterior_facets.local_facet_dat.data],
+                                 dtype=Mesh.face_id_dtype)
     ext_neighbor_faces = np.zeros(ext_element_faces.shape,
                                   dtype=Mesh.face_id_dtype)
     # If only using some of the cells, throw away unused cells and
@@ -315,7 +318,7 @@ def _get_firedrake_facial_adjacency_groups(fdrake_mesh_topology,
         ext_neighbor_faces = ext_neighbor_faces[to_keep]
 
     # tag the boundary
-    ext_neighbors = np.zeros(ext_elements.shape, dtype=np.int32)
+    ext_neighbors = np.zeros(ext_elements.shape, dtype=IntType)
     for ifac, marker in enumerate(top.exterior_facets.markers):
         ext_neighbors[ifac] = -(boundary_tag_bit(BTAG_ALL)
                                 | boundary_tag_bit(BTAG_REALLY_ALL)