Cross-Region data transfer check, retired so ZopNight raises no findings for it today

ZopNight retired this check

ZopNight no longer runs the High Cross-Region Data Transfer check, and it raises no findings for it today. The check used to read an account’s billed inter-Region transfer from Cost Explorer and count half of it as recoverable. That billing harvest was removed, and nothing replaced it: the transfer dollars stay inside the ordinary per-service billing rows, and CloudWatch network metrics have no destination dimension, so inter-Region bytes cannot be told apart from other egress. Rather than show a guessed figure, ZopNight retired the check. The page stays so existing links resolve and so the cost driver is still explained.

Traffic that leaves a Region is billed per GB

Moving data between AWS Regions is charged on the sending side. In billing data it appears under usage types named source-destination-AWS-Out-Bytes, such as USE1-USW2-AWS-Out-Bytes for US East (N. Virginia) to US West (Oregon). The AWS data transfer price list sets that pair at $0.02 per GB, the same as us-east-1 to Europe (Ireland) or Asia Pacific (Singapore).

At $0.02 a GB, 10 TB a month is about $200. The usual causes are a service in one Region calling a database or bucket in another, logs or metrics shipped to a central Region, and cross-Region replication that grew with the data.

Finding the Region pairs you pay for

aws ce get-cost-and-usage \
  --time-period Start=2026-08-01,End=2026-09-01 --granularity MONTHLY \
  --metrics UsageQuantity UnblendedCost \
  --group-by Type=DIMENSION,Key=USAGE_TYPE

Keep the rows ending in -AWS-Out-Bytes. The two Region codes in each name tell you the direction, UsageQuantity is the GB and UnblendedCost is what you paid.

Reading the number

Cost Explorer gives one total per Region pair for the account, not the instance, bucket or function that sent the bytes. Much cross-Region traffic is there on purpose, for disaster recovery, multi-Region availability and backups, so only the share that could run in one Region is worth chasing. Traffic between Availability Zones inside one Region is a separate usage type, covered on Cross-AZ Data Transfer Optimization Opportunity, which ZopNight has also retired.

Cutting inter-Region traffic

1. Rank the -AWS-Out-Bytes usage types by cost and name the service behind each Region pair.
2. Move chatty consumers into the same Region as the data they read, or add a read replica or cache in the consumer’s Region.
3. Compress and batch data that must cross, such as log shipping and replication streams.
4. Check replication rules for buckets and databases that copy more than recovery requires.
5. Re-run the Cost Explorer query a month later to confirm the Region pair’s cost fell.