diff --git a/cfgrib/xarray_store.py b/cfgrib/xarray_store.py
index d0a32cd9..b2b9a47b 100644
--- a/cfgrib/xarray_store.py
+++ b/cfgrib/xarray_store.py
@@ -42,6 +42,7 @@ def open_dataset(path, **kwargs):
 def merge_datasets(datasets, **kwargs):
     # type: (T.Sequence[xr.Dataset], T.Any) -> T.List[xr.Dataset]
     merged = []  # type: T.List[xr.Dataset]
+    first = []  # type: T.List[xr.Dataset]
     for ds in datasets:
         ds.attrs.pop("history", None)
         for i, o in enumerate(merged):
@@ -55,6 +56,19 @@ def merge_datasets(datasets, **kwargs):
                     pass
         else:
             merged.append(ds)
+            first.append(ds)
+
+    # Add the important coordinate encoding fields from the first found, to the merged:
+    preserve_encoding_fields = ["source", "units", "calendar", "dtype"]
+    for i, o in enumerate(first):
+        for var in o.coords:
+            out_encoding = {
+                key: o[var].encoding[key]
+                for key in preserve_encoding_fields
+                if key in o[var].encoding
+            }
+            merged[i][var].encoding.update(out_encoding)
+
     return merged
 
 
diff --git a/tests/test_40_xarray_store.py b/tests/test_40_xarray_store.py
index 541c8562..f14d70ae 100644
--- a/tests/test_40_xarray_store.py
+++ b/tests/test_40_xarray_store.py
@@ -159,6 +159,19 @@ def test_open_datasets_differet_step_types_zeros() -> None:
     assert res[1].cfrzr.attrs["GRIB_stepType"] == "avg"
 
 
+# ensure that the encoding of the coordinates is preserved
+def test_open_datasets_differet_preserve_coordinate_encoding() -> None:
+    res = xarray_store.open_datasets(TEST_DATA_DIFFERENT_STEP_TYPES)
+    assert len(res) == 2
+    assert "units" in res[0].valid_time.encoding
+    assert "units" in res[1].valid_time.encoding
+
+    res = xarray_store.open_datasets(TEST_DATA_DIFFERENT_STEP_TYPES_ZEROS)
+    assert len(res) == 2
+    assert "units" in res[0].valid_time.encoding
+    assert "units" in res[1].valid_time.encoding
+
+
 def test_open_dataset_steps_in_minutes() -> None:
     res = xarray_store.open_dataset(TEST_DATA_STEPS_IN_MINUTES)