# S3 Transfer Acceleration Enabled but Low Cross-Region Traffic

> Explains when S3 Transfer Acceleration costs more than it helps, and why ZopNight shows no dollar figure for it.

Source: https://zop.dev/integrations/aws/recommendations/s3-transfer-acceleration-enabled-but-low-cross-region-traffic

---

## What the accelerated endpoint charges

[S3 Transfer Acceleration](https://docs.aws.amazon.com/AmazonS3/latest/userguide/transfer-acceleration.html)
routes transfers through CloudFront edge locations to speed up long-distance uploads and downloads.
It only applies to requests sent to the `bucket-name.s3-accelerate.amazonaws.com` endpoint; the
regular endpoints keep working as before. The
[S3 pricing page](https://aws.amazon.com/s3/pricing/) lists the surcharge on top of normal data
transfer: $0.04 per GB for uploads accelerated through edge locations in the United States, Europe
and Japan, $0.08 per GB through all other edge locations, and $0.04 per GB for accelerated downloads
and inter-Region transfers. AWS does not charge when it judges that acceleration would not have been
faster for a given upload.

So leaving acceleration enabled is not a cost in itself. The cost comes from clients using the
accelerated endpoint for transfers that gain nothing, for example traffic from the same Region.

## Seeing which buckets have acceleration on

```bash
for b in $(aws s3api list-buckets --query 'Buckets[].Name' --output text); do
  echo "$b $(aws s3api get-bucket-accelerate-configuration --bucket $b --query Status --output text)"
done
```

For the buckets showing `Enabled`, search application configuration, SDK settings and upload
tools for the `s3-accelerate` endpoint to see who actually uses it.

## What ZopNight reads

ZopNight records whether Transfer Acceleration is enabled on each bucket. That tells it where the
lever exists, but not how many bytes went through the accelerated endpoint.

## Why no finding is ever shown

A dollar figure would need accelerated gigabytes per bucket. CloudWatch byte metrics do not separate
accelerated from regular traffic, and per-resource cost data does not break it out by usage type,
so ZopNight has no reliable source for it. Rather than show a $0 recommendation or a guess, the rule
raises no finding on any bucket. Treat this page as a checklist for your own review.

## What you would save

```text
saving = accelerated GB per month x acceleration surcharge per GB ($0.04 or $0.08)
```

Normal data transfer charges still apply after acceleration is suspended; only the surcharge goes.

## Suspending acceleration on a bucket

1. Find the clients using the accelerated endpoint and confirm they do not need it.
2. Point them at the regular regional endpoint.
3. Suspend acceleration, which requires `s3:PutAccelerateConfiguration`:
   `aws s3api put-bucket-accelerate-configuration --bucket my-bucket --accelerate-configuration Status=Suspended`
4. Re-enable it later with `Status=Enabled` if long-distance upload volume grows; AWS notes it can
   take up to 20 minutes before speeds improve after enabling.