diff --git a/pyproject.toml b/pyproject.toml
index 416e022..1d082ec 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -11,7 +11,7 @@ authors = [
 description = "Package to create NCAS AMOF netCDF files."
 readme = "README.md"
 license = {file = "LICENSE"}
-requires-python = ">=3.8, <4"
+requires-python = ">=3.9, <4"
 classifiers = [
     "Development Status :: 5 - Production/Stable",
     "Environment :: Console",