Tonga Cable: latency up to 2.2× normal, 29 Sep 2026
What we measured
| Cable | Tonga Cable |
| Segment | Nuku'alofa, TO → Suva, FJ |
| Detected | 2026-09-29 01:31 UTC |
| Resolved | 2026-09-29 04:02 UTC |
| Duration | 2h 30m |
| Observed latency | 71 ms |
| Baseline | 54.7 ms · 2.23× |
| Increase | +123% |
| Severity | critical |
Who is affected
Countries where Tonga Cable 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 |
|---|---|---|---|
| Fiji resilience index: 81 · resilient |
1 of 9 cables (11% of submarine diversity) | APX East, Bulikula, Gondwana-2/Picot-2 +5 more | median 352 ms today vs 384 ms over 30 days (49 routes) - unchanged |
| Tonga resilience index: 57 · moderate |
1 of 3 cables (33% of submarine diversity) | Hawaiki, Tonga Domestic Cable Extension (TDCE) | average 141 ms over the last day vs 225 ms over 30 days - faster |
Dependence is structural (share of the country's submarine cables), not a traffic share: real traffic distribution across cables is not public.
Vessels nearby at the time of the incident
No vessel activity was seen within 5 km of the cable route in the window from 48 hours before to 6 hours after the start (by AIS; vessels with transmitters off are not visible).
Path analysis
Traffic kept the same route. Latency rose without a visible path change, which points at congestion or a fault on the existing route rather than a reroute.
Cross-probe verdict. Too few independent vantage points were watching this endpoint to reach a cross-probe verdict.
Timeline
- Alert 2026092901: warning - ratio 2.23x
- Alert #213 improving: 1/3 consecutive OK
- Alert #213 improving: 2/3 consecutive OK
- Alert #213 resolved: RTT 71.01ms (baseline 54.71ms), 3 consecutive OK
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.