PGASCOM

Based on 116 RIPE Atlas measurements from GeoCables monitoring infrastructure, March–April 2026.

PGASCOM is a 264-kilometre regional submarine cable connecting Sakra Island in Singapore to two Indonesian landings: Batam in the Riau Archipelago and Kuala Tungkal on the southeast coast of Sumatra. The cable came into service in 2010 and is owned and operated by PT PGAS Telekomunikasi Nusantara (PGASCOM), a single-owner Indonesian carrier — and one of the more unusual ownership stories among regional Southeast Asian submarine systems. PGASCOM is a wholly-owned subsidiary of Perusahaan Gas Negara (PGN), Indonesia's state-owned gas utility company. The submarine cable was originally built to support telecommunications along PGN's natural gas pipeline infrastructure between Singapore, Batam, and the Sumatran gas fields, and grew into a commercial telecom service after the initial gas-industry use case had been provisioned. The cable's existence is a side effect of Indonesia's gas-distribution geography: PGN needed reliable telecom along its pipeline routes, so it built submarine fibre as part of the same project.

This kind of utility-owned submarine cable is uncommon globally but historically more frequent in Southeast Asia, where the geography of gas, oil, and power transmission has overlapped with the geography of inter-island internet connectivity. PGASCOM is the most operationally durable example in the Indonesia-Singapore corridor: it has been in commercial telecom service for fifteen years, the consortium ownership remains stable, and the cable has continued to operate alongside the consortium and private cables from other Indonesian carriers — Matrix Cable System, BRCS, DMCS, and the more recent RISING 8 — that share the same corridor and similar regional commercial role.

5.74 milliseconds when the route uses the cable

The single direction with substantial measurement coverage on PGASCOM is from Sakra Island in Singapore to Kuala Tungkal on the Sumatran coast. Across 116 measurements, the round-trip averages 67.38 ms, with a minimum of 5.74 ms, a maximum of 378.37 ms, and a standard deviation of 54.61 ms. The physics floor for the 264-km segment between Sakra Island and Kuala Tungkal is approximately 2.58 ms; the minimum we observe sits at 2.225× of that floor — about 5.74 ms over a 2.58-ms theoretical limit on a short regional cable.

The 5.74-ms minimum is the meaningful PGASCOM number for understanding the cable as physical infrastructure. It is a clean transit through 264 km of submarine fibre plus a small overhead for terminal-station optics — exactly what a healthy regional cable on a short route should produce. By comparison, Matrix Cable System on the Jakarta-Singapore segment shows 1.376× of its own floor, and RISING 8 on the Singapore-Java segment shows 1.317×. PGASCOM at 2.225× is a slightly higher multiplier, but this is a structural artefact of the very short cable: a 264-km cable has a theoretical floor of 2.58 ms, and small absolute-time additions from terminal-station equipment expand more dramatically as a multiplier than they do on a 1,000- or 2,000-km cable.

The same arithmetic on a longer cable would produce a smaller multiplier; the same cable measured with smarter terminal optics would also produce a smaller multiplier. PGASCOM is, in physical infrastructure terms, doing exactly what a 264-km regional cable should do: delivering Singapore-side traffic to its Indonesian destination at a few milliseconds of round-trip latency.

The wild variance: routing politics on a small cable

Beyond the 5.74-ms minimum, the rest of PGASCOM's Sakra-Kuala-Tungkal measurement profile is striking. The average of 67.38 ms is nearly twelve times the minimum. The maximum of 378.37 ms is sixty-six times the minimum. The standard deviation of 54.61 ms is over nine times the minimum value. Individual measurements scatter across a range that spans almost two orders of magnitude, despite the entire route being only 264 km long.

This is the same pattern we have documented on RISING 8 (sd 44.67 ms on a similar regional Singapore-Indonesia segment), BRCS (extreme asymmetry between forward and reverse), and DMCS (asymmetry plus high variance). What it reflects is that the Singapore-side carriers we measure from are not committing all their Indonesia-bound traffic to PGASCOM — some sessions go through the cable directly and register at the floor; others are routed onto alternative submarine cables (Matrix, RISING 8, BRCS, DMCS, B2JS, B3JS) that share the same Singapore-Indonesia corridor. PGASCOM is one of half a dozen regional cables competing for the same flows, and the BGP routing decisions that select among them produce the high variance we observe.

The economics of the corridor explain this competition. Singapore-Indonesia capacity is densely contested: Indonesian carriers have built multiple owned cables over the past two decades to provide outbound capacity for their domestic customer bases, and Singapore's peering ecosystem accepts traffic on any of them. For Singapore-side carriers, the choice among PGASCOM, Matrix, RISING 8, and the others is largely a matter of which IRU contracts they have active and how their BGP route preferences have been configured. PGASCOM's share of this competition appears to be modest — most measurements suggest the route is one option among many rather than the preferred path — but the 5.74-ms minimum confirms the cable functions when traffic does commit to it.

The gas-pipeline architecture

PGASCOM's three landings reflect the physical geography of PGN's gas distribution: Batam is the gas terminal for the Singapore-Indonesia gas pipeline, Kuala Tungkal is on the eastern Sumatran coast where PGN's pipeline reaches the open-water crossing, and Sakra Island is the Singapore-side gas terminal where PGN's pipeline lands in Singapore's industrial zone. The submarine fibre runs alongside the gas pipeline along the same submarine right-of-way, sharing the engineering surveys, the cable-laying ship operations, and the regulatory approval processes that gas-pipeline construction had already secured.

This is why PGASCOM has the landings it has, and why the cable has been operationally durable: the gas pipeline is a hard-wired commitment that gives the submarine fibre a long-term operational rationale beyond the commercial telecom market. The cable does not need to compete with Matrix, RISING 8, or the other regional alternatives on price alone — it has a primary use case (telecom for the gas-distribution operations of PGN) that secures its existence, and its commercial telecom service is a secondary product layered on top of that primary use case.

The Indonesian regional cable family is structurally diverse in ownership: Matrix is owned by an Indonesian carrier consortium, BRCS and DMCS by other carriers, RISING 8 by Moratelindo and Triasmitra, and PGASCOM by a gas utility subsidiary. Indonesia's 140-plus submarine cable landing points reflect this ownership diversity: many cables, many owners, many separate commercial agreements with Singapore-side carriers, and a market that has continued to add regional capacity year by year. PGASCOM is one of the older entries in this family, and its continued operation alongside newer cables is testament to the cable's structural advantages from its gas-pipeline origin.

What we will keep watching

The Sakra-to-Kuala-Tungkal direction we currently monitor on PGASCOM is the Singapore-out side of the corridor; reverse measurements from Kuala Tungkal back to Sakra Island would let us characterise the cable's Indonesia-out direction with similar depth. As GeoCables' probe network expands its Indonesian footprint, we expect to add that coverage. The Batam landing — which connects PGASCOM to the same Riau Archipelago hub as Matrix, BRCS, B2JS, and others — will also be worth monitoring directly once probe coverage allows.

What we measure on PGASCOM — 5.74 ms minimum across 264 km of submarine fibre, with wild variance from competing alternative routes on the Singapore-side BGP policies — is what a fifteen-year-old regional gas-utility-built cable looks like in 2026 when it operates alongside half a dozen other cables in the same corridor. The cable continues to do its job; it is just one of several options the corridor's BGP has to choose among at any given measurement window. Its share of the corridor's traffic will continue to evolve as new cables come online and existing cables go through their own commercial and regulatory cycles, and we will continue to track the Sakra-Kuala-Tungkal corridor as a measurement window into Indonesian regional connectivity.