diff --git a/.github/workflows/check-ros-distribution.sh b/.github/workflows/check-ros-distribution.sh
deleted file mode 100755
index c8715133c..000000000
--- a/.github/workflows/check-ros-distribution.sh
+++ /dev/null
@@ -1,12 +0,0 @@
-#!/usr/bin/env bash
-#
-# ./check-ros-distribution.sh <ROS distribution>
-# ROS distribution must match the directory name for this distribution
-# in /opt. E.g. melodic.
-
-readonly ROS_DISTRIBUTION="$1"
-
-# GitHub Action is erroneously setting PYTHONHOME to C:\python37
-unset PYTHONHOME
-source "/opt/ros/${ROS_DISTRIBUTION}/setup.bash"
-rosstack list
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 5c7b628c7..4fa6d1609 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -44,7 +44,6 @@ jobs:
       fail-fast: false
       matrix:
         docker_image:
-          - ubuntu:20.04
           - ubuntu:22.04
           - ubuntu:24.04
           - ubuntu:26.04
@@ -76,8 +75,6 @@ jobs:
         ros_distribution:
           # Humble Hawksbill (May 2022 - May 2027)
           - humble
-          # Iron Irwini (May 2023 - November 2024)
-          - iron
           # Jazzy Jalisco (May 2024 - May 2029)
           - jazzy
           # Kilted Kaiju (May 2025 - November 2026)
@@ -116,10 +113,6 @@ jobs:
         #
         # Platforms are defined in REP 3: https://ros.org/reps/rep-0003.html
         include:
-          # Noetic Ninjemys (May 2020 - May 2025)
-          - docker_image: ubuntu:focal
-            ros_distribution: noetic
-            ros_version: 1
 
           # Humble Hawksbill (May 2022 - May 2027)
           - docker_image: ubuntu:jammy
@@ -130,11 +123,6 @@ jobs:
             ros_distribution: humble
             ros_version: 2
 
-          # Iron Irwini (May 2023 - November 2024)
-          - docker_image: ubuntu:jammy
-            ros_distribution: iron
-            ros_version: 2
-
           # Jazzy Jalisco (May 2024 - May 2029)
           - docker_image: ubuntu:noble
             ros_distribution: jazzy
diff --git a/action.yml b/action.yml
index f935b79de..d99886a3f 100644
--- a/action.yml
+++ b/action.yml
@@ -26,9 +26,7 @@ inputs:
 
       Allowed ROS distributions
       - "" (no value) - no ROS binary installation
-      - noetic
       - humble
-      - iron
       - jazzy
       - kilted
       - lyrical