Incident report · 2026032801
Sirius South cable: latency up 37%, 28 Mar 2026
Resolved · 9h 56m
What we measured
| Cable | Sirius South |
| Segment | Dublin, IE → Blackpool, GB |
| Detected | 2026-03-28 19:33 UTC |
| Resolved | 2026-03-29 06:29 UTC |
| Duration | 9h 56m |
| Observed latency | 42.1 ms |
| Baseline | 30.8 ms · 1.37× |
| Increase | +149% |
| Severity | warning |
Who is affected
Countries where Sirius South comes ashore, how much of their submarine diversity this cable represents, and what our measurements into them show.
| Country | Dependence on this cable | Other submarine cables | What the measurements show |
|---|---|---|---|
| Ireland resilience index: 100 · resilient |
1 of 16 cables (6% of submarine diversity) | AEC-1, Beaufort, CeltixConnect-1 (CC-1) +12 more | median 73 ms today vs 62 ms over 30 days (180 routes) - slower |
| United Kingdom resilience index: 100 · resilient |
1 of 68 cables (1% of submarine diversity) | 2Africa, Amitie, Apollo +64 more | median 103 ms today vs 74 ms over 30 days (1011 routes) - slower |
Dependence is structural (share of the country's submarine cables), not a traffic share: real traffic distribution across cables is not public.
Path analysis
No usable traceroute data for this window.
Cross-probe verdict. Multiple independent probes saw the same degradation, so this was not a local artefact.
Timeline
- Alert #27: warning - Blackpool
- Alert #27 resolved: Blackpool
Detection method
Latency is sampled continuously from our probe network. An alert opens when round-trip time to a monitored endpoint holds above its rolling baseline, and closes automatically once it returns. Full method is described on the methodology page.
How to cite
GeoCables (2026). Incident 2026032801: Sirius South. https://geocables.com/incident/2026032801
Embed this map
<iframe src="https://geocables.com/embed.php?type=map&id=sirius-south" width="640" height="420" frameborder="0" loading="lazy" style="border:0;border-radius:10px"></iframe>