diff --git a/CHANGELOG.md b/CHANGELOG.md
index ffc9bd3786f76fcab8093a135297b8b0dd9a41d7..74bc3f04d0e1ffadfcceb54284dbf903dff1aebe 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -15,7 +15,8 @@ SPDX-License-Identifier: GPL-3.0-or-later
 - Remove all flag value restrictions from the default flagging scheme `FloatTranslator` 
 - Renamed `TranslationScheme.forward` to `TranslationScheme.toInternal` 
 - Renamed `TranslationScheme.backward` to `TranslationScheme.toExternal` 
-- Changed Default value of the parameter `limit` for `SaQC.interpolateIndex` and `SaQC.interpolateInvalid` to ``None`
+- Changed default value of the parameter `limit` for `SaQC.interpolateIndex` and `SaQC.interpolateInvalid` to ``None``
+- Changed default value of the parameter ``overwrite`` for ``concatFlags`` to ``False``
 ### Removed
 ### Fixed
 
diff --git a/saqc/funcs/resampling.py b/saqc/funcs/resampling.py
index 5dce6b0094a4c9e81be706a16c398adba84fd38a..c7dcf511e5a25b0345ff65c4556993bee2d736ac 100644
--- a/saqc/funcs/resampling.py
+++ b/saqc/funcs/resampling.py
@@ -337,7 +337,7 @@ class ResamplingMixin:
         freq: str | None = None,
         drop: bool = False,
         squeeze: bool = False,
-        overwrite: bool = True,
+        overwrite: bool = False,
         **kwargs,
     ) -> "SaQC":
         """
@@ -395,7 +395,7 @@ class ResamplingMixin:
             If set to `True`, the appended flags frame will be squeezed - resulting in function specific flags informations
             getting lost.
 
-        overwrite: bool, default True
+        overwrite: bool, default False
             If set to True, the newly appended flags will overwrite exsiting flags. This might result in a loss of previous
             flagging information.
 
@@ -471,6 +471,7 @@ class ResamplingMixin:
                     "freq": freq,
                     "drop": drop,
                     "squeeze": squeeze,
+                    "overwrite": overwrite,
                     **kwargs,
                 },
             }
diff --git a/tests/funcs/test_functions.py b/tests/funcs/test_functions.py
index c898cb8af6658f1ca424a25564fb345e2faf5402..4ef82002ab488b0322ba50f531fcc03063a38231 100644
--- a/tests/funcs/test_functions.py
+++ b/tests/funcs/test_functions.py
@@ -101,7 +101,9 @@ def test_flagSesonalRange(data, field):
             flag=BAD,
         )
         qc = qc.flagRange(newfield, min=test["min"], max=test["max"], flag=BAD)
-        qc = qc.concatFlags(newfield, method="match", target=field, flag=BAD)
+        qc = qc.concatFlags(
+            newfield, method="match", target=field, flag=BAD, overwrite=True
+        )
         qc = qc.dropField(newfield)
         flagged = qc._flags[field] > UNFLAGGED
         assert flagged.sum() == expected