diff --git a/.ci_support/environment.yml b/.ci_support/environment.yml
index 4b4f1491c..0327ead30 100644
--- a/.ci_support/environment.yml
+++ b/.ci_support/environment.yml
@@ -13,7 +13,7 @@ dependencies:
 - phonopy =4.5.0
 - plotly =7.0.0
 - pymatgen =2026.5.4
-- pyscal3 =3.3.2
+- pyscal3 =4.0.0
 - scikit-learn =1.9.1
 - scipy =1.18.0
 - spglib =2.7.0
diff --git a/pyproject.toml b/pyproject.toml
index 66c24f351..5a0900bba 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -41,7 +41,7 @@ grainboundary = [
     "aimsgb==1.1.1",
     "pymatgen==2026.5.4",
 ]
-pyscal = ["pyscal3==3.3.2"]
+pyscal = ["pyscal3==4.0.0"]
 nglview = ["nglview==4.0.1"]
 matplotlib = ["matplotlib==3.11.2"]
 plotly = ["plotly==7.0.0"]