diff --git a/wake_t/diagnostics/openpmd_diag.py b/wake_t/diagnostics/openpmd_diag.py
index 51bb9ba0..cb75b4aa 100644
--- a/wake_t/diagnostics/openpmd_diag.py
+++ b/wake_t/diagnostics/openpmd_diag.py
@@ -307,9 +307,7 @@ def _write_fields(self, it, wf_data):
                 fld.set_attribute(attr, val)
             fld.axis_labels = wf_data[field]['grid']['labels']
             fld.grid_spacing = wf_data[field]['grid']['spacing']
-            global_offset = deepcopy(wf_data[field]['grid']['global_offset'])
-            global_offset[-1] += self._current_z_pos
-            fld.grid_global_offset = global_offset
+            fld.grid_global_offset = wf_data[field]['grid']['global_offset']
 
     def check_species_names(
         self,