AWS permit users read/list access to a prefix in a bucket

s3_read_only_prefix_policy.json

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                "s3:ListBucket"
            ],
            "Resource": [
                "arn:aws:s3:::fancy-bucket"
            ],
            "Condition": {
                "StringLike": {
                    "s3:prefix": [
                        "fancy-prefix/*"
                    ]
                }
            }
        },
        {
            "Effect": "Allow",
            "Action": [
                "s3:Get*"
            ],
            "Resource": "arn:aws:s3:::fancy-bucket/fancy-prefix/*"
        }
    ]
}

I often need to provide a user access to a single prefix path in S3. And I always forget how to do it. Here is a policy that does this. Attach it to the IAM user who needs this access.