Can an S3 bucket be shared with another AWS account?

Three ways to share

• A bucket policy, a rule on the bucket, that names their account. Simplest; they then allow their own people to use it.
• An IAM role, a role they borrow, with an external ID, a secret code, in the handshake so nobody else can. The safer pattern for vendors and services.
• An access point, a side door: one address and one set of rules per partner, so the bucket policy never becomes a list of everyone you have ever worked with.

Moving a bucket

Bucket names belong to the account that created them, so a bucket cannot change hands. To move the files, create a bucket in the other account, let it read yours, and copy.

$5per million files

the copy, billed as fetches

$20per TB

on top, if the two buckets are in different Amazon regions