diff --git a/src/coordinate_transformation_api/crs_transform.py b/src/coordinate_transformation_api/crs_transform.py
index f78af26..7c036ba 100644
--- a/src/coordinate_transformation_api/crs_transform.py
+++ b/src/coordinate_transformation_api/crs_transform.py
@@ -341,6 +341,32 @@ def get_individual_epsg_code(compound_crs: CRS) -> tuple[str, str]:
     return (f"{horizontal[0]}:{horizontal[1]}", f"{vertical[0]}:{vertical[1]}")
 
 
+def build_input_coord(coord: CoordinatesType, epoch: float | None) -> CoordinatesType:
+
+    # When 2D input is given with an epoch we need to add a height. So pyproj knows to
+    # that the epoch is an epoch and not the height, without this intervention the epoch
+    # would be place in the firth position of the tuple.
+    if len(coord) == TWO_DIMENSIONAL and epoch is not None:
+        return tuple([*coord, 0.0, epoch])
+
+    # Default behaviour
+    # The input_coord == coord that are given. When an epoch is provided with a 3D coord
+    # this is added or the value None is given for any other. Note: with 2D the additional None
+    # is the height. But this doesn't influence the result, because it's None.
+    input_coord = tuple(
+        [
+            *coord,
+            (
+                float(epoch)
+                if len(coord) == THREE_DIMENSIONAL and epoch is not None
+                else None
+            ),
+        ]
+    )
+
+    return input_coord
+
+
 def get_transform_crs_fun(  #
     source_crs: str,
     target_crs: str,
@@ -414,16 +440,7 @@ def transform_crs(val: CoordinatesType) -> tuple[float, ...]:
             # when one of the src or tgt crs has a dynamic time component
             # or the transformation used has a datetime component
             # for now simple check on coords length (which is not correct)
-            input = tuple(
-                [
-                    *val,
-                    (
-                        float(epoch)
-                        if len(val) == THREE_DIMENSIONAL and epoch is not None
-                        else None
-                    ),
-                ]
-            )
+            input = build_input_coord(val, epoch)
 
             # GeoJSON and CityJSON by definition has coordinates always in lon-lat-height (or x-y-z) order. Transformer has been created with `always_xy=True`,
             # to ensure input and output coordinates are in in lon-lat-height (or x-y-z) order.
diff --git a/tests/data/test_2d_with_epoch.json b/tests/data/test_2d_with_epoch.json
new file mode 100644
index 0000000..4b75d45
--- /dev/null
+++ b/tests/data/test_2d_with_epoch.json
@@ -0,0 +1,8 @@
+{
+  "type": "Feature",
+  "properties": {},
+  "geometry": {
+    "type": "Point",
+    "coordinates": [663000.0, 5781000.0]
+  }
+}
diff --git a/tests/test_geojson_transformation.py b/tests/test_geojson_transformation.py
index a279a04..ec474fe 100644
--- a/tests/test_geojson_transformation.py
+++ b/tests/test_geojson_transformation.py
@@ -162,6 +162,60 @@ def test_validate_crs_transformed_geojson(feature):
         validate_crs_transformed_geojson(feature_no_exc)
 
 
+def test_2d_with_epoch():
+    with open("tests/data/test_2d_with_epoch.json") as f:
+        data = json.load(f)
+        feature_2d_2000 = Feature(**data)
+        feature_2d_2020 = Feature(**data)
+        feature_2d_org = Feature(**data)
+
+        crs_transform(feature_2d_2000, "EPSG:3043", "EPSG:32631", 2000)
+        crs_transform(feature_2d_2020, "EPSG:3043", "EPSG:32631", 2020)
+
+        assert feature_2d_2000 != feature_2d_org
+        assert feature_2d_2020 != feature_2d_org
+
+        coords_2000 = feature_2d_2000.geometry.coordinates
+        coords_2020 = feature_2d_2020.geometry.coordinates
+        coords_org = feature_2d_org.geometry.coordinates
+
+        dif_2000_org = 0.29
+        dif_2020_org = 0.76
+
+        assert (
+            round(
+                math.sqrt(
+                    (
+                        (coords_2000[0] - coords_org[0])
+                        * (coords_2000[0] - coords_org[0])
+                    )
+                    + (
+                        (coords_2000[1] - coords_org[1])
+                        * (coords_2000[1] - coords_org[1])
+                    )
+                ),
+                2,
+            )
+            == dif_2000_org
+        )
+        assert (
+            round(
+                math.sqrt(
+                    (
+                        (coords_2020[0] - coords_org[0])
+                        * (coords_2020[0] - coords_org[0])
+                    )
+                    + (
+                        (coords_2020[1] - coords_org[1])
+                        * (coords_2020[1] - coords_org[1])
+                    )
+                ),
+                2,
+            )
+            == dif_2020_org
+        )
+
+
 def test_wgs_epoch():
     with open("tests/data/test_wgs_epoch.json") as f:
         data = json.load(f)
diff --git a/tests/test_transformer_selection.py b/tests/test_transformer_selection.py
index a1b807a..b7795e5 100644
--- a/tests/test_transformer_selection.py
+++ b/tests/test_transformer_selection.py
@@ -1,5 +1,9 @@
 import pytest
-from coordinate_transformation_api.crs_transform import get_transformer, needs_epoch
+from coordinate_transformation_api.crs_transform import (
+    build_input_coord,
+    get_transformer,
+    needs_epoch,
+)
 
 
 # This test needs the modified proj.time.dependent.transformations.db from
@@ -17,3 +21,16 @@
 )
 def test_time_dependant_operation_method(source, target, epoch, expectation):
     assert needs_epoch(get_transformer(source, target, epoch)) == expectation
+
+
+@pytest.mark.parametrize(
+    ("coord", "epoch", "expectation"),
+    [
+        (tuple([1000.0, 1000.0]), 2000.0, tuple([1000.0, 1000.0, 0.0, 2000.0])),
+        (tuple([1000.0, 1000.0]), None, tuple([1000.0, 1000.0, None])),
+        (tuple([1000.0, 1000.0, 10.0]), 2000.0, tuple([1000.0, 1000.0, 10.0, 2000.0])),
+        (tuple([1000.0, 1000.0, 10.0]), None, tuple([1000.0, 1000.0, 10.0, None])),
+    ],
+)
+def test_build_input_coord(coord, epoch, expectation):
+    assert build_input_coord(coord, epoch) == expectation