diff --git a/.ci_support/environment.yml b/.ci_support/environment.yml
index 6475c5232..d1c947f5d 100644
--- a/.ci_support/environment.yml
+++ b/.ci_support/environment.yml
@@ -12,7 +12,7 @@ dependencies:
 - numpy =2.5.3
 - phonopy =4.5.0
 - plotly =7.1.0
-- pymatgen =2026.5.4
+- pymatgen =2026.9.24
 - pyscal3 =3.3.2
 - scikit-learn =1.9.1
 - scipy =1.18.1
diff --git a/binder/environment.yml b/binder/environment.yml
index eb0d6c32c..23255b270 100644
--- a/binder/environment.yml
+++ b/binder/environment.yml
@@ -10,7 +10,7 @@ dependencies:
 - numpy =2.5.3
 - phonopy =4.3.1
 - plotly =6.9.0
-- pymatgen =2026.5.4
+- pymatgen =2026.9.24
 - pyscal3 =3.3.2
 - scikit-learn =1.8.0
 - scipy =1.18.1
diff --git a/pyproject.toml b/pyproject.toml
index 125a36f94..fa378457b 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -39,7 +39,7 @@ Repository = "https://github.com/pyiron/structuretoolkit"
 dscribe = ["dscribe==2.1.2"]
 grainboundary = [
     "aimsgb==1.1.1",
-    "pymatgen==2026.5.4",
+    "pymatgen==2026.9.24",
 ]
 pyscal = ["pyscal3==3.3.2"]
 nglview = ["nglview==4.0.1"]
@@ -49,7 +49,7 @@ clusters = ["scikit-learn==1.9.1"]
 symmetry = ["spglib==2.7.0"]
 surface = [
     "spglib==2.7.0",
-    "pymatgen==2026.5.4",
+    "pymatgen==2026.9.24",
 ]
 phonopy = [
     "phonopy==4.5.0",
@@ -57,7 +57,7 @@ phonopy = [
 ]
 mp-api = [
     "mp-api==0.45.15",
-    "pymatgen==2026.5.4",
+    "pymatgen==2026.9.24",
 ]
 
 [tool.ruff]