diff --git a/Dockerfile b/Dockerfile
index 06588ad..60198c0 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -3,7 +3,7 @@
 # github: perrygeo/docker-gdal-base
 # docker: perrygeo/gdal-base
 #----------------------------------- #
-FROM python:3.8-slim-buster as builder
+FROM python:3.9-slim-buster as builder
 
 RUN apt-get update
 RUN apt-get install -y --no-install-recommends \
diff --git a/README.md b/README.md
index 335ca60..b64e6a7 100644
--- a/README.md
+++ b/README.md
@@ -24,7 +24,7 @@ See [`perrygeo/gdal-base` on Dockerhub](https://hub.docker.com/r/perrygeo/gdal-b
 
 ## Packages and version numbers
 
-Dockerfiles are based on [`python:3.8-slim-buster`](https://github.com/docker-library/python/blob/master/3.8/buster/slim/Dockerfile) which in turn is based on Debian 10/Buster.
+Dockerfiles are based on [`python:3.9-slim-buster`](https://github.com/docker-library/python/blob/master/3.9/buster/slim/Dockerfile) which in turn is based on Debian 10/Buster.
 
 The following versions built from source:
 
@@ -90,7 +90,7 @@ RUN pip uninstall cython --yes
 
 # ------ Second stage
 # Start from a clean image
-FROM python:3.8-slim-buster as final
+FROM python:3.9-slim-buster as final
 
 # Install some required runtime libraries from apt
 RUN apt-get update \
diff --git a/tests/Dockerfile.test b/tests/Dockerfile.test
index f2b02b0..35461a2 100644
--- a/tests/Dockerfile.test
+++ b/tests/Dockerfile.test
@@ -7,7 +7,7 @@ RUN pip uninstall cython --yes
 
 # ------ Second stage
 # Start from a clean image
-FROM python:3.6-slim-stretch as final
+FROM python:3.9-slim-stretch as final
 
 # Install some required runtime libraries from apt
 RUN apt-get update \