diff --git a/x-pack/test_serverless/functional/config.base.ts b/x-pack/test_serverless/functional/config.base.ts
index 23739a9615e69..95496431dede9 100644
--- a/x-pack/test_serverless/functional/config.base.ts
+++ b/x-pack/test_serverless/functional/config.base.ts
@@ -27,6 +27,7 @@ export function createTestConfig(options: CreateTestConfigOptions) {
         serverArgs: [
           ...svlSharedConfig.get('kbnTestServer.serverArgs'),
           `--serverless=${options.serverlessProject}`,
+          '--xpack.encryptedSavedObjects.encryptionKey="wuGNaIhoMpk5sO4UBxgr3NyW1sFcLgIf"',
         ],
       },
       testFiles: options.testFiles,