diff --git a/.github/workflows/pytests.yml b/.github/workflows/pytests.yml
index 35628f7f..eba1d271 100644
--- a/.github/workflows/pytests.yml
+++ b/.github/workflows/pytests.yml
@@ -83,13 +83,13 @@ jobs:
 
             git clone https://github.com/phonopy/phonopy
             cd phonopy
-            echo python3 -m pip install --no-build-isolation -c $PIP_CONSTRAINTS -e . -vvv
+            echo python3 -m pip install -c $PIP_CONSTRAINTS -e . -vvv
             python3 -m pip install -c $PIP_CONSTRAINTS -e . -vvv
             cd ..
 
             git clone https://github.com/phonopy/phono3py
             cd phono3py
-            python3 -m pip install --no-build-isolation -c $PIP_CONSTRAINTS -e . -vvv
+            python3 -m pip install -c $PIP_CONSTRAINTS -e . -vvv
             cd ..
 
       - name: Install Quippy from PyPI