diff --git a/cdk/lib/__snapshots__/mobile-save-for-later.test.ts.snap b/cdk/lib/__snapshots__/mobile-save-for-later.test.ts.snap
index 7f3a4d3..09d85f5 100644
--- a/cdk/lib/__snapshots__/mobile-save-for-later.test.ts.snap
+++ b/cdk/lib/__snapshots__/mobile-save-for-later.test.ts.snap
@@ -96,6 +96,7 @@ Object {
           ],
         },
         "DomainName": "mobile-save-for-later.mobile-aws.code.dev-guardianapis.com",
+        "SecurityPolicy": "TLS_1_2",
         "Tags": Array [
           Object {
             "Key": "gu:cdk:version",
@@ -1289,6 +1290,7 @@ Object {
           ],
         },
         "DomainName": "mobile-save-for-later.mobile-aws.guardianapis.com",
+        "SecurityPolicy": "TLS_1_2",
         "Tags": Array [
           Object {
             "Key": "gu:cdk:version",
diff --git a/cdk/lib/mobile-save-for-later.ts b/cdk/lib/mobile-save-for-later.ts
index 8757b12..1ff88e6 100644
--- a/cdk/lib/mobile-save-for-later.ts
+++ b/cdk/lib/mobile-save-for-later.ts
@@ -128,6 +128,7 @@ export class MobileSaveForLater extends GuStack {
     const cfnDomainName = new CfnDomainName(this, "ApiDomainName", {
       domainName: props.domainName,
       certificateArn,
+      securityPolicy: "TLS_1_2",
     });
 
     new CfnBasePathMapping(this, "ApiMapping", {