diff --git a/.gitallowed b/.gitallowed
index a7cacaea4980e..20a94b7dae003 100644
--- a/.gitallowed
+++ b/.gitallowed
@@ -25,6 +25,7 @@ account: '422531588944'
 account: '924023996002'
 account: '919366029133' #cn-north-1
 account: '919830735681' #cn-northwest-1
+account: '909464085924' #ap-southeast-3
 
 # The account IDs of password rotation applications of Serverless Application Repository
 # https://docs.aws.amazon.com/secretsmanager/latest/userguide/enable-rotation-rds.html
diff --git a/packages/@aws-cdk/region-info/build-tools/fact-tables.ts b/packages/@aws-cdk/region-info/build-tools/fact-tables.ts
index f901f99dbf1b2..6578ee94d4d95 100644
--- a/packages/@aws-cdk/region-info/build-tools/fact-tables.ts
+++ b/packages/@aws-cdk/region-info/build-tools/fact-tables.ts
@@ -171,6 +171,7 @@ export const APPMESH_ECR_ACCOUNTS: { [region: string]: string } = {
   'ap-south-1': '840364872350',
   'ap-southeast-1': '840364872350',
   'ap-southeast-2': '840364872350',
+  'ap-southeast-3': '909464085924',
   'ca-central-1': '840364872350',
   'cn-north-1': '919366029133',
   'cn-northwest-1': '919830735681',