Lower Indian Ocean Network 2 (LION2)

Based on 21 RIPE Atlas measurements from GeoCables monitoring infrastructure, March–April 2026.

LION-2 — short for Lower Indian Ocean Network 2 — is a 2,700-kilometre submarine cable connecting Nyali in Mombasa, Kenya, to Kaweni on the French overseas department of Mayotte, with the cable continuing onward in the wider LION network to Madagascar, Réunion, and Mauritius. The cable came into service in 2012 and is owned by a six-member consortium of Indian Ocean operators: Emtel and Mauritius Telecom on Mauritius, Orange and Société Réunionnaise du Radiotéléphone on Réunion, Orange Madagascar on Madagascar, and Telkom Kenya on the Kenyan mainland. LION-2 is the second-generation expansion of the original LION cable system, which entered service in 2009 connecting Madagascar to Réunion and Mauritius; LION-2 added Kenya and Mayotte to that footprint, extending the network onto the East African coast and bringing the French-administered Comorian island of Mayotte into the regional submarine fabric.

The cable's defining structural feature is its role as the principal regional submarine connection for the southwest Indian Ocean island states. Mauritius, Réunion, Madagascar, the Comoros, and Mayotte sit far from any continental landing — the nearest mainland is the Kenyan and Tanzanian coast, several hundred to a few thousand kilometres away, depending on which island — and historically have been served by a thin set of submarine cables. SEA-ME-WE-4 and the EASSy and SEACOM cables along the East African coast carry the bulk of mainland-Africa international traffic, but the Indian Ocean island states have always required dedicated regional infrastructure to reach those mainland systems. LION-2 is the regional connector that does that work for the northern part of this ecosystem.

Below the floor: 0.235× of theoretical

The single direction we currently monitor on LION-2 is from Nyali in Kenya to Kaweni on Mayotte. Across 21 measurements, the round-trip averages 6.31 ms, with a minimum of 6.20 ms, a maximum of 6.64 ms, and a standard deviation of 0.15 ms. The traceroute median is just 4 hops. The physics floor for the cable's nominal full 2,700-km length is 26.42 ms; the minimum we observe sits at 0.235× of that floor. Far below the floor.

This is the most extreme below-floor measurement in the GeoCables monitoring set. The interpretation is the same as EXA North and South at 0.716× across the Atlantic and ARCOS-1 at 0.613× in the Caribbean — the route the packet actually takes is shorter than the cable's nominal advertised length — but on LION-2 the gap between observed transit time and theoretical full-length floor is dramatic. The 6.20-ms minimum implies an actual physical path of approximately 635 km between Nyali and Kaweni, which corresponds to the great-circle distance between Mombasa and Mayotte — roughly the segment of LION-2 that connects only those two landings, not the full cable from Mombasa onward through Mayotte to Madagascar to Réunion to Mauritius.

The 2,700-km figure on LION-2 is the total wet-plant length across the multi-segment system, not the length of any single point-to-point path within it. When we measure latency between just two landings — Nyali and Kaweni — we observe only the length of that one segment, plus a small overhead for landing-station optics. The 0.235× multiplier captures this geometric truth precisely: the route uses approximately 23.5% of the cable's full length, which is exactly the share of LION-2's wet plant that lies between the Kenyan and Mayotte landings.

0.15-millisecond stability across two-thirds of a millisecond range

Beyond the below-floor anomaly, the LION-2 measurement profile is remarkable for its stability. The standard deviation of 0.15 ms across 21 samples is one of the tightest measurement profiles in our entire cable set. Every individual round-trip falls within a window of less than half a millisecond, and the entire range from minimum to maximum is just 0.44 ms wide. Compare this with regional cables like RISING 8, which shows 44.67 ms standard deviation on a similar Singapore-Indonesia regional segment — the difference reflects how completely committed the route policy is to LION-2 for Kenya-Mayotte traffic.

This is what a single-purpose regional cable looks like when there is no commercial alternative for the corridor it serves. Nyali-to-Kaweni traffic essentially has no other path: the alternative routings would go all the way through East African mainland fibre to South Africa, then across to Madagascar, then onward to Mayotte — a route that would multiply the latency by something like 20-30×. The carriers we measure from on the Kenyan end commit traffic to LION-2 because there is no other reasonable option, and the resulting measurement profile is a clean, stable, single-route observation of an underutilised cable doing exactly what it was built to do.

Mayotte and the French Indian Ocean network

The Mayotte landing of LION-2 is one of the few high-capacity submarine connections that this small French overseas department has into the wider internet. Mayotte's geographic position — between Madagascar and the African mainland, in the Mozambique Channel — makes it an unusual candidate for submarine cable landings, since traffic to and from the island has to navigate either across Madagascar or directly to the East African coast. LION-2 takes the latter route, giving Mayotte a direct fibre connection to Mombasa that bypasses Madagascar entirely. For the island's residents and the local government services that depend on internet connectivity, this 6-millisecond link to the East African mainland is the principal physical infrastructure that connects them to global networks.

Réunion, Mauritius, and Madagascar — the original LION cable's three landings — remain connected to the wider system through LION's earlier segments and through several other regional cables (METISS, Bharat-Lanka, SAFE, and others). The combination of LION-1 and LION-2 forms the backbone of intra-island French Indian Ocean connectivity, and the consortium ownership structure — with Orange and Société Réunionnaise on Réunion, Mauritius Telecom and Emtel on Mauritius, and Orange Madagascar — reflects the regional carrier base that depends most directly on the network's continued operation.

What we will keep watching

The Nyali-Kaweni measurement is one direction of LION-2's broader system, and the cable's other segments — Madagascar to Réunion to Mauritius — would show their own distinctive measurement profiles if probe coverage in the Indian Ocean island states allowed direct testing. As GeoCables' probe network expands its footprint, we expect to add measurements on those segments as well. East African connectivity history is largely written through cables like LION-2, the EASSy and SEACOM systems on the mainland, and the SEA-ME-WE family that crosses the Indian Ocean from further north.

What we measure on LION-2 — 6.20 ms minimum across what is nominally a 2,700-km cable, sitting at 0.235× of that nominal length's physics floor, with 0.15-ms variance across the entire measurement window — is one of the cleanest examples in our set of how submarine cable geometry actually works. The cable is doing precisely what it was built to do for the Kenya-Mayotte corridor, and the floor multiplier of 0.235× is the structural signal that this is one segment of a larger system rather than a point-to-point cable used end-to-end.