diff --git a/doc/release_notes.rst b/doc/release_notes.rst
index 8388946f8..461e4d1a5 100644
--- a/doc/release_notes.rst
+++ b/doc/release_notes.rst
@@ -10,6 +10,8 @@ Release Notes
 Upcoming Release
 ================
 
+* In simplifying polygons in :mod:`build_shapes` default to no tolerance.
+
 * Set non-zero capital_cost for methanol stores to avoid unrealistic storage sizes
 
 * Set p_nom = p_nom_min for generators with baseyear == grouping_year in add_existing_baseyear. This has no effect on the optimization but helps n.statistics to correctly report already installed capacities.
diff --git a/scripts/build_shapes.py b/scripts/build_shapes.py
index 85afdaea4..8eaea9f0f 100644
--- a/scripts/build_shapes.py
+++ b/scripts/build_shapes.py
@@ -91,7 +91,7 @@ def _get_country(target, **keys):
         return np.nan
 
 
-def _simplify_polys(polys, minarea=0.1, tolerance=0.01, filterremote=True):
+def _simplify_polys(polys, minarea=0.1, tolerance=None, filterremote=True):
     if isinstance(polys, MultiPolygon):
         polys = sorted(polys.geoms, key=attrgetter("area"), reverse=True)
         mainpoly = polys[0]
@@ -106,7 +106,9 @@ def _simplify_polys(polys, minarea=0.1, tolerance=0.01, filterremote=True):
             )
         else:
             polys = mainpoly
-    return polys.simplify(tolerance=tolerance)
+    if tolerance is not None:
+        polys = polys.simplify(tolerance=tolerance)
+    return polys
 
 
 def countries(naturalearth, country_list):