How do I reduce data transfer charges for my NAT gateway in Amazon VPC?

Resolution

Prerequisite: Identify the sources of traffic through your NAT gateway. You can use Amazon CloudWatch to monitor your NAT gateway

To reduce data transfer and processing charges, take the following actions:

• Check whether the resources behind the NAT gateway that send the most traffic are in the same Availability Zone as the NAT gateway. If the resources are in a different Availability Zone, then create a new NAT gateway in the same Availability Zone as the resource. Data transfer within the same Availability Zone is free.
• Check whether majority of your charges are from traffic to Amazon Simple Storage Service (Amazon S3) or Amazon DynamoDB in the same AWS Region. If the charges are in the same Region as your NAT gateway, then set up a gateway VPC endpoint. Make sure that you route traffic to and from the AWS resource through the gateway VPC endpoint instead of through the NAT gateway.
  Note: When you use gateway VPC endpoints, you don't receive data processing or hourly charges.
• If the majority of your charges are from traffic to Amazon S3 or DynamoDB in a different Region, then access Amazon S3 through an Amazon S3 interface endpoint.
• If a majority of your NAT gateway traffic is directed towards AWS services that support interface VPC endpoints, then create an interface VPC endpoint. For more information on cost savings, see AWS PrivateLink pricing.
• Use AWS Trusted Advisor to check whether your configured your NAT gateways with Availability Zone independence. Availability Zone independence helps to avoid cross-zone data transfer charges and fault tolerant architecture.

Related information

Queries for NAT gateway

Query Amazon VPC flow logs

Using AWS Cost Explorer to analyze data transfer costs