AWS VPC Peering Data Transfer Costs Across Different Accounts (Same Region & AZ)

Question

I would like to clarify the data transfer pricing behavior for AWS VPC Peering when the peered VPCs are in different AWS accounts, but located in the same AWS Region and the same Availability Zone (AZ). The goal is to understand when costs are incurred and under what traffic conditions.

Questions

1. For VPC Peering between different AWS accounts in the same Region and same AZ, does AWS charge data transfer fees, or is it treated the same as intra-AZ traffic?
2. If charges apply, which pricing category is used:
* Inter-VPC data transfer?
* Inter-AZ data transfer?
3. Another specific VPC Peering data transfer rate, at what point does pricing start to incur?
* On all traffic over the peering connection?
* Only when traffic crosses AZ boundaries?
* Only for ingress, egress, or both?
4. Are data transfer costs billed to the requester VPC, acceptor VPC, or both accounts?

Sukhman Singh · Accepted Answer

For VPC peering between different AWS accounts in the same Region and same Availability Zone, AWS does not charge any data transfer fees for traffic between the peered VPCs; this traffic is treated as regular intra-AZ communication with no cost for ingress or egress, regardless of which account initiates the connection, and billing does not apply to either the requester or acceptor VPC accounts—costs would only be incurred if the traffic crossed AZ boundaries (inter-AZ data transfer rates) or left the Region entirely, but within the same AZ, all peered VPC traffic remains free.

re:Post Agent · Answer

For VPC Peering between different AWS accounts in the same Region and same Availability Zone (AZ), data transfer is free. AWS has specifically made all data transfer over a VPC Peering connection that stays within an Availability Zone free of charge, regardless of whether the VPCs belong to different AWS accounts.

To address your specific questions:

1. VPC Peering between different AWS accounts in the same Region and same AZ is free. The account ownership doesn't affect this pricing benefit - as long as the traffic stays within the same AZ, there are no data transfer charges.

2. Since there are no charges for same-AZ VPC peering traffic, this pricing category question doesn't apply. However, if your traffic were to cross AZ boundaries, it would fall under inter-AZ data transfer pricing.

3. Pricing only begins to incur when:
- Traffic crosses Availability Zone boundaries (charged at standard in-region data transfer rates)
- Traffic crosses Region boundaries (charged at standard inter-Region data transfer rates)

Traffic that stays within the same AZ remains free, regardless of volume.

4. When charges do apply (for cross-AZ or cross-Region traffic), data transfer costs are typically billed to both accounts. The sending account is charged for outbound data transfer, and the receiving account is charged for inbound data transfer. This means both the requester and acceptor VPC owners may incur charges depending on the direction of traffic flow.

It's worth noting that AWS has also made inter-AZ data transfer free for some other networking services like AWS Transit Gateway, AWS PrivateLink, and AWS Client VPN, but the free same-AZ VPC peering has been in place for some time.  
**Sources**  
[VPC peering in-out data transfer when the traffic is within the same Availability Zone | AWS re:Post](https://repost.aws/questions/QUB3j07_W5QB22-oH6kNXsjA/vpc-peering-in-out-data-transfer-when-the-traffic-is-within-the-same-availability-zone)  
[VPC peering - Building a Scalable and Secure Multi-VPC AWS Network Infrastructure](https://docs.aws.amazon.com/whitepapers/latest/building-scalable-secure-multi-vpc-network-infrastructure/vpc-peering.html)  
[Amazon VPC peering - General SAP Guides](https://docs.aws.amazon.com/sap/latest/general/rise-connection-peering.html)  
[Questions about Data trasnfer charge ** | AWS re:Post](https://repost.aws/questions/QUmabUhMC8Qhi8vV-pUWrBkQ/questions-about-data-trasnfer-charge)

AWS VPC Peering Data Transfer Costs Across Different Accounts (Same Region & AZ)

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