diff --git a/infra/config/global/generated/cr-buildbucket.cfg b/infra/config/global/generated/cr-buildbucket.cfg
index cba8483..f561258 100644
--- a/infra/config/global/generated/cr-buildbucket.cfg
+++ b/infra/config/global/generated/cr-buildbucket.cfg
@@ -14,7 +14,7 @@
       name: "cmake-linux-clang-dbg-x64"
       swarming_host: "chromium-swarm.appspot.com"
       dimensions: "cpu:x86-64"
-      dimensions: "os:Ubuntu-22.04"
+      dimensions: "os:Ubuntu-18.04"
       dimensions: "pool:luci.flex.ci"
       recipe {
         name: "dawn/cmake"
@@ -33,7 +33,7 @@
       name: "cmake-linux-clang-dbg-x64-asan"
       swarming_host: "chromium-swarm.appspot.com"
       dimensions: "cpu:x86-64"
-      dimensions: "os:Ubuntu-22.04"
+      dimensions: "os:Ubuntu-18.04"
       dimensions: "pool:luci.flex.ci"
       recipe {
         name: "dawn/cmake"
@@ -52,7 +52,7 @@
       name: "cmake-linux-clang-dbg-x64-ubsan"
       swarming_host: "chromium-swarm.appspot.com"
       dimensions: "cpu:x86-64"
-      dimensions: "os:Ubuntu-22.04"
+      dimensions: "os:Ubuntu-18.04"
       dimensions: "pool:luci.flex.ci"
       recipe {
         name: "dawn/cmake"
@@ -71,7 +71,7 @@
       name: "cmake-linux-clang-rel-x64"
       swarming_host: "chromium-swarm.appspot.com"
       dimensions: "cpu:x86-64"
-      dimensions: "os:Ubuntu-22.04"
+      dimensions: "os:Ubuntu-18.04"
       dimensions: "pool:luci.flex.ci"
       recipe {
         name: "dawn/cmake"
@@ -90,7 +90,7 @@
       name: "cmake-linux-clang-rel-x64-asan"
       swarming_host: "chromium-swarm.appspot.com"
       dimensions: "cpu:x86-64"
-      dimensions: "os:Ubuntu-22.04"
+      dimensions: "os:Ubuntu-18.04"
       dimensions: "pool:luci.flex.ci"
       recipe {
         name: "dawn/cmake"
@@ -109,7 +109,7 @@
       name: "cmake-linux-clang-rel-x64-ubsan"
       swarming_host: "chromium-swarm.appspot.com"
       dimensions: "cpu:x86-64"
-      dimensions: "os:Ubuntu-22.04"
+      dimensions: "os:Ubuntu-18.04"
       dimensions: "pool:luci.flex.ci"
       recipe {
         name: "dawn/cmake"
@@ -218,7 +218,7 @@
       name: "cron-linux-clang-rel-x64"
       swarming_host: "chromium-swarm.appspot.com"
       dimensions: "cpu:x86-64"
-      dimensions: "os:Ubuntu-22.04"
+      dimensions: "os:Ubuntu-18.04"
       dimensions: "pool:luci.flex.ci"
       recipe {
         name: "dawn/gn"
@@ -236,7 +236,7 @@
       name: "cts-roller"
       swarming_host: "chromium-swarm.appspot.com"
       dimensions: "cpu:x86-64"
-      dimensions: "os:Ubuntu-22.04"
+      dimensions: "os:Ubuntu-18.04"
       dimensions: "pool:luci.flex.ci"
       recipe {
         name: "dawn/roll_cts"
@@ -268,7 +268,7 @@
       name: "linux-clang-dbg-x64"
       swarming_host: "chromium-swarm.appspot.com"
       dimensions: "cpu:x86-64"
-      dimensions: "os:Ubuntu-22.04"
+      dimensions: "os:Ubuntu-18.04"
       dimensions: "pool:luci.flex.ci"
       recipe {
         name: "dawn/gn"
@@ -286,7 +286,7 @@
       name: "linux-clang-dbg-x86"
       swarming_host: "chromium-swarm.appspot.com"
       dimensions: "cpu:x86-64"
-      dimensions: "os:Ubuntu-22.04"
+      dimensions: "os:Ubuntu-18.04"
       dimensions: "pool:luci.flex.ci"
       recipe {
         name: "dawn/gn"
@@ -304,7 +304,7 @@
       name: "linux-clang-rel-x64"
       swarming_host: "chromium-swarm.appspot.com"
       dimensions: "cpu:x86-64"
-      dimensions: "os:Ubuntu-22.04"
+      dimensions: "os:Ubuntu-18.04"
       dimensions: "pool:luci.flex.ci"
       recipe {
         name: "dawn/gn"
@@ -322,7 +322,7 @@
       name: "linux-clang-rel-x86"
       swarming_host: "chromium-swarm.appspot.com"
       dimensions: "cpu:x86-64"
-      dimensions: "os:Ubuntu-22.04"
+      dimensions: "os:Ubuntu-18.04"
       dimensions: "pool:luci.flex.ci"
       recipe {
         name: "dawn/gn"
@@ -534,7 +534,7 @@
       name: "cmake-linux-clang-dbg-x64"
       swarming_host: "chromium-swarm.appspot.com"
       dimensions: "cpu:x86-64"
-      dimensions: "os:Ubuntu-22.04"
+      dimensions: "os:Ubuntu-18.04"
       dimensions: "pool:luci.flex.try"
       recipe {
         name: "dawn/cmake"
@@ -554,7 +554,7 @@
       name: "cmake-linux-clang-dbg-x64-asan"
       swarming_host: "chromium-swarm.appspot.com"
       dimensions: "cpu:x86-64"
-      dimensions: "os:Ubuntu-22.04"
+      dimensions: "os:Ubuntu-18.04"
       dimensions: "pool:luci.flex.try"
       recipe {
         name: "dawn/cmake"
@@ -574,7 +574,7 @@
       name: "cmake-linux-clang-dbg-x64-ubsan"
       swarming_host: "chromium-swarm.appspot.com"
       dimensions: "cpu:x86-64"
-      dimensions: "os:Ubuntu-22.04"
+      dimensions: "os:Ubuntu-18.04"
       dimensions: "pool:luci.flex.try"
       recipe {
         name: "dawn/cmake"
@@ -594,7 +594,7 @@
       name: "cmake-linux-clang-rel-x64"
       swarming_host: "chromium-swarm.appspot.com"
       dimensions: "cpu:x86-64"
-      dimensions: "os:Ubuntu-22.04"
+      dimensions: "os:Ubuntu-18.04"
       dimensions: "pool:luci.flex.try"
       recipe {
         name: "dawn/cmake"
@@ -614,7 +614,7 @@
       name: "cmake-linux-clang-rel-x64-asan"
       swarming_host: "chromium-swarm.appspot.com"
       dimensions: "cpu:x86-64"
-      dimensions: "os:Ubuntu-22.04"
+      dimensions: "os:Ubuntu-18.04"
       dimensions: "pool:luci.flex.try"
       recipe {
         name: "dawn/cmake"
@@ -634,7 +634,7 @@
       name: "cmake-linux-clang-rel-x64-ubsan"
       swarming_host: "chromium-swarm.appspot.com"
       dimensions: "cpu:x86-64"
-      dimensions: "os:Ubuntu-22.04"
+      dimensions: "os:Ubuntu-18.04"
       dimensions: "pool:luci.flex.try"
       recipe {
         name: "dawn/cmake"
@@ -763,7 +763,7 @@
       name: "linux-clang-dbg-x64"
       swarming_host: "chromium-swarm.appspot.com"
       dimensions: "cpu:x86-64"
-      dimensions: "os:Ubuntu-22.04"
+      dimensions: "os:Ubuntu-18.04"
       dimensions: "pool:luci.flex.try"
       recipe {
         name: "dawn/gn"
@@ -782,7 +782,7 @@
       name: "linux-clang-dbg-x86"
       swarming_host: "chromium-swarm.appspot.com"
       dimensions: "cpu:x86-64"
-      dimensions: "os:Ubuntu-22.04"
+      dimensions: "os:Ubuntu-18.04"
       dimensions: "pool:luci.flex.try"
       recipe {
         name: "dawn/gn"
@@ -801,7 +801,7 @@
       name: "linux-clang-rel-x64"
       swarming_host: "chromium-swarm.appspot.com"
       dimensions: "cpu:x86-64"
-      dimensions: "os:Ubuntu-22.04"
+      dimensions: "os:Ubuntu-18.04"
       dimensions: "pool:luci.flex.try"
       recipe {
         name: "dawn/gn"
@@ -820,7 +820,7 @@
       name: "linux-clang-rel-x86"
       swarming_host: "chromium-swarm.appspot.com"
       dimensions: "cpu:x86-64"
-      dimensions: "os:Ubuntu-22.04"
+      dimensions: "os:Ubuntu-18.04"
       dimensions: "pool:luci.flex.try"
       recipe {
         name: "dawn/gn"
@@ -885,7 +885,7 @@
       name: "presubmit"
       swarming_host: "chromium-swarm.appspot.com"
       dimensions: "cpu:x86-64"
-      dimensions: "os:Ubuntu-22.04"
+      dimensions: "os:Ubuntu-18.04"
       dimensions: "pool:luci.flex.try"
       recipe {
         name: "run_presubmit"
diff --git a/infra/config/global/main.star b/infra/config/global/main.star
index fb4e485..2a1d892 100755
--- a/infra/config/global/main.star
+++ b/infra/config/global/main.star
@@ -150,7 +150,7 @@
 def get_dimension(os, builder_name = None):
     """Returns the dimension to use for the input os and optional builder name"""
     if os.category == os_category.LINUX:
-        return "Ubuntu-22.04"
+        return "Ubuntu-18.04"
     elif os.category == os_category.MAC:
         if "cmake" in builder_name:
             # CMake build runs Tint e2e tests, which must run on 11+ where the metal