I have an S3 bucked in the Asia Pacific (Sydney) region and have users from Australia using that bucket.

By far my largest charge is for AWS Data Transfer APS2-USE1-AWS-Out-Bytes Asia Pacific (Sydney) data transfer to US East (Northern Virginia).

However I do not have replication turned on for the Sydney bucket.

I do have some buckets in the US East (Northern Virginia) but I am not seeing any data being transferred to into them. So why am I being charged for the inter region transfers?


If you want, you can enable S3 server access logging to show the IP address of the source. Maybe its one of your servers downloading data from that bucket? Or do you have public access enabled - it might not be you downloading content at all, and they just happen to be accessing from us-east-1.

  • I will have a look – Obromios Mar 26 '20 at 0:26

Are you sure that the transfer costs are associated to S3? Could it be some other resource in your AWS infrastructure causing it? EC2, RDS replication, VPC Peering, etc?

If you're 100% sure it's S3 here are some possible reasons:

  • CloudFront in the US is downloading data from your Sydney S3 before serving the customers.
  • You've got other resources in US-East that access the data in S3, e.g. EC2 instances?
  • Some periodic access from the US going on (e.g. Route53 health check?)
  • S3 Access logging to the US bucket
  • Some clients of yours are in fact in the US and not in Sydney?

My bet though is that the charge is not related to S3. Of course I could be wrong.

Hope that helps :)

  • I am CloudFlare, for web access, so will examine that. – Obromios Mar 26 '20 at 0:30
  • @MLu traffic out from any service to CloudFront is always free and has its own billing SKUs. – Michael - sqlbot Mar 26 '20 at 20:52

It turned out that I had logging turned on for the Sydney bucket, and the logs were being sent to a bucket in the US East (Northern Virginia) region. Not a good idea.

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