SeaMeWe-4

Based on 38 RIPE Atlas measurements from GeoCables monitoring infrastructure, March–April 2026.

SEA-ME-WE-4 — short for Southeast Asia–Middle East–Western Europe 4 — is a 20,000-kilometre submarine cable that connects fourteen countries across three regions in a single multi-landing trunk. The cable came into service in 2005 and is owned by a sixteen-member consortium that includes Algérie Télécom, Bangladesh Submarine Cable Company (BSCCL), Bharti Airtel, National Telecom Thailand, Orange, Pakistan Telecommunications Company, Singtel, Sparkle (the international arm of Telecom Italia), Sri Lanka Telecom, Tata Communications, Telecom Egypt, Telekom Malaysia, Tunisia Telecom, Verizon, center3 (Saudi Arabia), and e& (formerly Etisalat, UAE). The cable is the fourth in the SEA-ME-WE family — a sequence of consortium cables along this corridor that began with SEA-ME-WE-1 in 1985 and has continued through SEA-ME-WE-6 (2025), each one progressively higher capacity and at slightly different routing — and remains one of the workhorse Asia-Europe systems two decades after it lit.

SEA-ME-WE-4 lands at sixteen points across the corridor: Tuas in Singapore, Satun in Thailand, melaka in Malaysia, Chennai and Mumbai in India, Colombo in Sri Lanka, Cox's Bazar in Bangladesh, Karachi in Pakistan, Fujairah in the UAE, Jeddah in Saudi Arabia, Suez and Alexandria in Egypt, Bizerte in Tunisia, Annaba in Algeria, Palermo in Italy, and Marseille in France. The combined customer base reachable from these landings runs to roughly two billion people. SEA-ME-WE-4 is one of the small set of cables for which the question is not whether it carries internet traffic for a particular country, but how much.

What 1.191× over twenty thousand kilometres looks like

The single direction we currently monitor is from Tuas in Singapore to Marseille in France — the longest commercial latency-budget on the system. Across 38 measurements, the round-trip averages 263.91 ms, with a minimum of 233.10 ms, a maximum of 587.30 ms, and a standard deviation of 64.01 ms. The traceroute median is 24-26 hops. The physics floor for a 20,000-kilometre route is 195.74 ms; the minimum we observe sits at 1.191× that floor.

That multiplier — about 19% above the theoretical limit — is the signature of a clean multi-segment trunk transit when the route policy actually commits to it. The minimum measurement of 233 ms is what SEA-ME-WE-4 produces when the path is using its full Asia-to-Europe wet plant in a single straight transit through Singapore, the Indian Ocean, the Egyptian crossing (using the Suez segment plus terrestrial backhaul to Alexandria and onward via the Mediterranean), and the western Mediterranean approach to Marseille. That number competes with what newer high-capacity cables on the same corridor produce, with the wet plant in 2026 still operating well within the latency budget the original 2005 engineering set.

The variance, however, is significant. The standard deviation of 64 ms across 38 samples means individual measurements spread across a wide range, and the 587-millisecond maximum suggests that some sessions take dramatically longer paths — most likely re-routing onto sister cables in the same corridor when SEA-ME-WE-4 sees congestion or a localised cut. MENA Cable is one of the natural alternates, and the Asia-Europe corridor has half a dozen others that share Egyptian transit. The SEA-ME-WE-4 multiplier as we observe it is structurally similar to MENA at 1.525× — both cables share the Suez crossing, the Mediterranean approach, and the same routing constraint that dictates a terrestrial component within a nominally submarine system.

Twenty-one years of Asia-Europe service

SEA-ME-WE-4 entered service in 2005 — three years younger than the SEA-ME-WE-3 it was meant to supplement, and twenty years older than the SEA-ME-WE-6 that arrived in 2025. The longevity is itself the headline. Cables in this corridor have historically been the backbone of Indian, Pakistani, and Bangladeshi internet connectivity to Europe, and the SEA-ME-WE family carries a substantial fraction of the traffic between South Asia and the rest of the world. Each generation of the family has added capacity rather than retiring earlier ones; SEA-ME-WE-3 (1999) is still in service, SEA-ME-WE-4 (2005) is still in service, SEA-ME-WE-5 (2016) is still in service, and SEA-ME-WE-6 (2025) joins them rather than replacing any of them. This is structurally similar to the Atlantic, where EXA North and South from 2001 still operates alongside the newer Marea and Amitié cables of the 2020s — long-haul submarine cables tend to outlast their original commercial assumptions.

The consortium ownership structure is unusual for the modern era. SEA-ME-WE-4's sixteen-owner list includes both national incumbent telcos (Algérie Télécom, Tunisia Telecom, Pakistan Telecom, Bangladesh's BSCCL) and globally operating carrier-of-carriers (Verizon, Orange, Tata Communications, Sparkle). Each owner holds a fixed share of fibre pairs and has the right to use them as they wish: for their own customer traffic, for IRU sales to third parties, or for transit settlement with other consortium members. This shared-ownership model is what made it possible to build a 20,000-kilometre Asia-Europe cable in 2005 that no single operator could have financed alone, and the same model has been replicated in each subsequent SEA-ME-WE generation. MENA Cable, by contrast, is single-owner GBI — the modern alternative model, where one private carrier-of-carriers builds the wet plant and sells slabs of capacity to whoever wants them.

The Egyptian crossing, again

SEA-ME-WE-4 has two Egyptian landings — Suez on the Red Sea coast and Alexandria on the Mediterranean — and the cable's transit between them is overland through Egyptian territory. This is the same architectural pattern as MENA, the same pattern as SEA-ME-WE-3 and SEA-ME-WE-5, and the same pattern that any Asia-Europe submarine cable in this corridor must adopt. The Sinai Peninsula is not crossed by submarine fibre; every Asia-Europe cable that uses the Red Sea-to-Mediterranean route lands on the Egyptian Red Sea coast, crosses the country by terrestrial backhaul, and re-enters the sea on the Mediterranean side. Telecom Egypt, as one of SEA-ME-WE-4's sixteen owners, operates the Egyptian terrestrial component and collects the transit fees that make Egypt one of the most strategically important telecommunications transit countries on the planet.

The latency consequence of this architecture is the 19% gap between the SEA-ME-WE-4 minimum and its physics floor. The wet plant alone, between Tuas and Marseille along the underwater route, would measure closer to its theoretical limit; the Egyptian terrestrial component plus segment-boundary multiplexing and amplification pushes the multiplier from approximately 1.05× (a clean submarine-only equivalent) up to the observed 1.191×. This is intrinsic to the corridor and is shared by every cable that uses it.

What we will keep watching

The single direction of measurement on SEA-ME-WE-4 is the longest one (Singapore-Marseille); the cable's value, however, is most clearly anchored in the shorter intra-corridor segments — Karachi-to-Mumbai, Chennai-to-Colombo, Jeddah-to-Suez, Mumbai-to-Fujairah, and so on. To characterise SEA-ME-WE-4 as users in any of its sixteen landing countries actually experience it, additional probe deployments closer to the cable's regional segments will be needed. Until then, the 233 ms Tuas-to-Marseille minimum is a credible upper-bound benchmark — what the cable produces when it is asked to deliver the longest latency budget it has, in clean transit, after twenty-one years of operation. Iran's submarine cable footprint, the Red Sea cable damage events of recent years, and the broader history of Asia-Europe submarine connectivity all sit on top of cables like SEA-ME-WE-4. The structural facts about the corridor — Egyptian transit, multi-landing geometry, mature peering — are the same facts that this cable's measurements illustrate.

What we measure on SEA-ME-WE-4 — 233 ms minimum across 20,000 kilometres of Asia-to-Europe submarine fibre, with variance that reflects the live trade-offs of competing alternative paths — is what a flagship Asia-Europe cable looks like in 2026 with two decades of accumulated commercial discipline behind it. The cable will continue carrying its share of South Asian and Middle Eastern internet traffic to Europe for as long as the consortium keeps upgrading its terminal optics, and the corridor as a whole will continue depending on it as one of the workhorse routes that hold the Asia-Europe internet together.