Amazon Virtual Private Cloud (VPC) now supports IPv6 traffic over Inter-Region VPC Peering. With this launch, your resources in different AWS regions, can communicate with each other using IPv6 addresses without requiring gateways, VPN connections, or separate physical hardware. Inter-Region VPC Peering encrypts inter-region traffic with no single point of failure or bandwidth bottleneck. Traffic using Inter-Region VPC Peering always stays on the AWS global network and never traverses the public internet.
Source:: Amazon AWS