Egress-Only Internet Gateway

Provides a functionality similar to that of a NAT gateway for IPv4, for IPv6.

IPv6 addresses are publicly routable, there’s no concept of 'private' IPv6 address, so incoming connections need to be blocked on purpose.

Egress-Only Internet Gateway provides connectivity to IPv6 VPC resource without allowing incoming connections.

You create the gateway (like any Internet Gateway), attach it to the VPC and then update the rouye table for the subnets you need to use that gateway for ::/0.