How do we keep our S3 data replicas in other regions?

Use S3 cross region replication.

Steps to do this:

1. Create buckets in desired regions
2. Enable versioning on both buckets
3. Go to the properties of the source bucket > Enable Cross region replication > Select source and target, bucket and region and IAM role > Done

Things to keep in mind!

1. Only the new objects will be copied, old data has to be copied by you
2. This cannot be done in the same region

Hope it helps!