February 14, 2025: This post was updated with the recommendation to restrict S3 bucket access to an IAM role by using the aws:PrincipalArn condition key instead of the aws:userid condition key. April 2, 2021: In the section “Granting cross-account bucket access to a specific IAM role,” we …

An AWS Identity and Access Management (IAM) role is an IAM identity that you create in your AWS account that has specific permissions. An IAM role is similar to an IAM user because it’s an AWS identity with permission policies that determine what the identity can and cannot …