diff --git a/images/releng/k8s-ci-builder/variants.yaml b/images/releng/k8s-ci-builder/variants.yaml
index 80e84163518..876cac8a071 100644
--- a/images/releng/k8s-ci-builder/variants.yaml
+++ b/images/releng/k8s-ci-builder/variants.yaml
@@ -2,7 +2,7 @@ variants:
   default:
     CONFIG: default
     GO_VERSION: '1.21.0'
-    OS_CODENAME: 'bookworm'
+    OS_CODENAME: 'bullseye'
   next:
     CONFIG: next
     GO_VERSION: '1.21.0'
@@ -10,7 +10,7 @@ variants:
   '1.29':
     CONFIG: '1.29'
     GO_VERSION: '1.21.0'
-    OS_CODENAME: 'bookworm'
+    OS_CODENAME: 'bullseye'
   '1.28':
     CONFIG: '1.28'
     GO_VERSION: '1.20.7'