diff --git a/db/post_migrate/20250917093907_change_workspaces_agent_config_dns_zone_default.rb b/db/post_migrate/20250917093907_change_workspaces_agent_config_dns_zone_default.rb
new file mode 100644
index 0000000000000000000000000000000000000000..135627feb0e2a7df080d8e84b630b679d1f41772
--- /dev/null
+++ b/db/post_migrate/20250917093907_change_workspaces_agent_config_dns_zone_default.rb
@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+class ChangeWorkspacesAgentConfigDnsZoneDefault < Gitlab::Database::Migration[2.3]
+  milestone '18.5'
+
+  def up
+    change_column_default :workspaces_agent_configs, :dns_zone, from: nil, to: ""
+  end
+
+  def down
+    change_column_default :workspaces_agent_configs, :dns_zone, from: "", to: nil
+  end
+end
diff --git a/db/schema_migrations/20250917093907 b/db/schema_migrations/20250917093907
new file mode 100644
index 0000000000000000000000000000000000000000..57df1b4d13a3913c6b44f0d51f54282741193e63
--- /dev/null
+++ b/db/schema_migrations/20250917093907
@@ -0,0 +1 @@
+541cb32972b3a51fb9c4ee2f4f62aaae06203b023abb91a35e03408f234ec198
\ No newline at end of file
diff --git a/db/structure.sql b/db/structure.sql
index 213cfc5bb853bd743fe40d64d378055af23a0f50..2183ba790bb95662b92641fa428f61d9c73b9c56 100644
--- a/db/structure.sql
+++ b/db/structure.sql
@@ -27626,7 +27626,7 @@ CREATE TABLE workspaces_agent_configs (
     project_id bigint NOT NULL,
     enabled boolean NOT NULL,
     network_policy_enabled boolean DEFAULT true NOT NULL,
-    dns_zone text NOT NULL,
+    dns_zone text DEFAULT ''::text NOT NULL,
     gitlab_workspaces_proxy_namespace text DEFAULT 'gitlab-workspaces'::text NOT NULL,
     network_policy_egress jsonb DEFAULT '[{"allow": "0.0.0.0/0", "except": ["10.0.0.0/8", "172.16.0.0/12", "192.168.0.0/16"]}]'::jsonb NOT NULL,
     default_resources_per_workspace_container jsonb DEFAULT '{}'::jsonb NOT NULL,
diff --git a/ee/app/models/remote_development/workspaces_agent_config.rb b/ee/app/models/remote_development/workspaces_agent_config.rb
index 908e45dd1dd7df79f4b442c3bb6f01bb6e7de325..8f5fd5a559cb892e57054c224c788bd09cda323a 100644
--- a/ee/app/models/remote_development/workspaces_agent_config.rb
+++ b/ee/app/models/remote_development/workspaces_agent_config.rb
@@ -6,6 +6,9 @@ class WorkspacesAgentConfig < ApplicationRecord
     #       https://gitlab.com/gitlab-org/gitlab/-/issues/410045#note_1385602915
 
     include Sortable
+    include SafelyChangeColumnDefault
+
+    columns_changing_default :dns_zone
 
     UNLIMITED_QUOTA = -1
     MIN_HOURS_BEFORE_TERMINATION = 1