ZAZ Cross-Region Latency

Round-trip time from AWS eu-south-2 (Spain / Aragón) to every other AWS commercial region.

Origin: eu-south-2 (Aragón, Spain)

Destinations: 34 regions

Window: rolling 1 week

Percentile

Region group

≤ 60 ms · same continent, sync replication feasible 60–180 ms · transatlantic / regional hop > 180 ms · trans-oceanic, async only

#	City	Region	IATA	Latency ▼		Band

Want the whole picture? See the full 35 × 35 region-to-region matrix →

Data source & methodology

Source: CloudPing.co — AWS Region Latency Matrix, community-maintained by Matt Aimonetti. Public JSON endpoint: https://www.cloudping.co/api/latencies?percentile={p_10|p_50|p_99}&timeframe=1W
Measurement: A t3.nano EC2 instance in every AWS commercial region opens periodic TCP connections to every other region and records round-trip time. Values reflect public-internet EC2 ↔ EC2 TCP handshakes, not ICMP ping and not the AWS backbone.
Aggregation window: Rolling 1 week, refreshed several times per day at source. Snapshot on this page captured 2026-09-12.
Percentiles: p10 is the fast-path (10% of samples are faster). p50 is the median. p99 is the tail — 1 in 100 samples is at least this slow. Design SLAs against p99, not p50.
Coverage: 34 destination regions. GovCloud (us-gov-*) and China (cn-*) regions are isolated environments and cannot be probed from commercial accounts, so they are absent by design.
Caveats:
- Traffic over Transit Gateway, VPC peering, PrivateLink, or the AWS backbone is often lower and less jittery than these numbers.
- Bahrain (me-south-1) shows identical p10/p50/p99 — a sparse-sampling artifact in the source, not a suspiciously stable link.
- Sub-millisecond precision here is spurious; treat values as ±3 ms.
Reproduce: curl 'https://www.cloudping.co/api/latencies?percentile=p_50&timeframe=1W' | jq '.data["eu-south-2"]'

Sources considered

Six public sources were evaluated. Only one is used here — the others measure a different thing, have no API, or are dead.

Source	Method	API	Verdict
CloudPing.co	EC2 → EC2 TCP, all 35 regions	Yes, JSON	Used here. Only public source with p10/p50/p99, 1D/1W/1M/1Y windows, and full N×N coverage.
awsspeedtest.com	Browser → S3 HTTPS	No	Client-to-region only. Adds ~20–40 ms of browser/TLS overhead vs. EC2 probes. Good for a laptop-side sanity check.
cloudping.info	Browser HTTP ping	No	Single-shot only. Not the Adorjan tool — that's `.co`. Fine for one-off checks, no history.
cloudpingtest.com	Browser HTTPS, multi-cloud	No	Useful for comparing AWS vs. GCP/Azure from your location, not for inter-region.
ThousandEyes (Cisco)	Enterprise probes, TCP + BGP	Paywalled	Quarterly PDF cloud performance report — good for order-of-magnitude citations, not real-time.
AWS Reachability Analyzer / Internet Monitor	Your own account traffic	Account only	Not public — AWS does not publish an inter-region latency matrix.

Dead / dropped: cloudharmony.com (Gartner shut it down), perfops.net/latency (404), aws-latency-test.com (empty shell).

Want an independent second opinion? Run 30 Lambda-to-Lambda TCP probes for a day — about 50 lines of Python. That gives you a private dataset to compare against CloudPing's public one.

Design guidance

The Aurora Global Database RPO of < 1 s needs consistent single-digit-to-low-double-digit latency — only eu-west-3 (Paris, ~18 ms) qualifies as a comfortable secondary. eu-central-2, eu-south-1, eu-west-2 all work with a bit more replay lag.
For async DR anywhere in Europe or the eastern US the p50 is under 100 ms — pick by service catalog and price, not latency.

Regional shortcuts

Closest neighbour: eu-west-3 Paris — 18 ms via terrestrial fibre through the French border. Best pick for synchronous replication.
Bedrock / SageMaker fallback: eu-central-1 Frankfurt — 31 ms, richest service catalog in EU.
EU sovereignty: eusc-de-east-1 European Sovereign Cloud (Brandenburg) — 105 ms, higher because it currently routes through a limited number of PoPs.
Americas gateway: us-east-1 N. Virginia — 97 ms, the standard cross-Atlantic pivot.
Asia entry point: ap-south-1 Mumbai — 119 ms, shortest hop to Asia via the SEA-ME-WE cable path.