Incident report · 2026040401
Southeast Asia-Japan Cable (SJC): latency up 15%, 4 Apr 2026
Resolved · 4h 17m
What we measured
| Cable | Southeast Asia-Japan Cable (SJC) |
| Segment | Tuas, SG → Chikura, JP |
| Detected | 2026-04-04 05:00 UTC |
| Resolved | 2026-04-04 09:17 UTC |
| Duration | 4h 17m |
| Observed latency | 122.7 ms |
| Baseline | 106.9 ms · 1.15× |
| Increase | +414% |
| Severity | critical |
Who is affected
Countries where Southeast Asia-Japan Cable (SJC) 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 |
|---|---|---|---|
| Brunei resilience index: 58 · moderate |
1 of 5 cables (20% of submarine diversity) | Asia Link Cable (ALC), Asia United Gateway East (AUG East), Asia-America Gateway (AAG) Cable System +1 more | no measurement today; median 281 ms over 30 days (33 routes) |
| China resilience index: 100 · resilient |
1 of 24 cables (4% of submarine diversity) | APCN-2, Asia Africa Europe-1 (AAE-1), Asia Direct Cable (ADC) +20 more | median 159 ms today vs 160 ms over 30 days (99 routes) - unchanged |
| Japan resilience index: 100 · resilient |
1 of 53 cables (2% of submarine diversity) | 5 Villages 6 Islands, APCN-2, Apricot +49 more | median 225 ms today vs 203 ms over 30 days (468 routes) - unchanged |
| Philippines resilience index: 100 · resilient |
1 of 26 cables (4% of submarine diversity) | APCN-2, Apricot, Asia Connect Cable-1 (ACC-1) +22 more | median 284 ms today vs 244 ms over 30 days (102 routes) - slower |
| Singapore resilience index: 78 · resilient |
1 of 46 cables (2% of submarine diversity) | APCN-2, Apricot, Asia Connect Cable-1 (ACC-1) +42 more | median 155 ms today vs 163 ms over 30 days (509 routes) - unchanged |
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. Too few independent vantage points were watching this endpoint to reach a cross-probe verdict.
Timeline
- Alert #40: critical - Chikura
- Alert #40 improving: 1/3 consecutive OK checks
- Alert #40 improving: 2/3 consecutive OK checks
- Alert #40 resolved: RTT 122.7ms (baseline 106.91ms)
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 2026040401: Southeast Asia-Japan Cable (SJC). https://geocables.com/incident/2026040401
Embed this map
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