What Are LEO Satellites? Why Are LEOs Better Than GEOs for Internet at Sea?

Anyone who has worked on a commercial vessel knows the ritual. You queue for the shared terminal, wait for the spinning cursor, and hope your video call does not freeze mid-sentence when you are trying to speak to family back home. For decades, that was simply the cost of being at sea. The technology -- GEO VSAT -- was doing its best, but the physics were always working against it.

LEO satellites changed that calculus. In the past few years, we have seen a genuine step-change in what maritime internet looks like, and vessels operating across Southeast Asia can now run cloud applications, real-time vessel monitoring, and crew video calls that would have been unthinkable five years ago. Understanding why requires a closer look at the difference between Low Earth Orbit and the older geostationary approach, and what that difference means for a ship in the middle of the South China Sea.

What Are LEO Satellites? Orbit, Speed, and Scale

A Low Earth Orbit (LEO) satellite operates at altitudes typically between 550 and 1,200 kilometres above the Earth's surface. That sounds high, but compare it to a Geostationary Earth Orbit (GEO) satellite, which sits at approximately 35,786 kilometres above the equator, and the distinction becomes very concrete.

The shorter the distance between a satellite and the vessel below, the less time a signal takes to travel up and back down. Physics is non-negotiable here. A signal to a GEO satellite travels roughly 72,000 kilometres in a single round trip. A signal to a LEO satellite might travel only 1,200 kilometres each way. That difference in distance is the root cause of every meaningful performance gap between the two technologies.

Because LEO satellites move across the sky quickly -- they are not stationary like GEO birds -- a single satellite cannot cover a fixed point on Earth for long. The solution is scale: operators deploy constellations of hundreds or thousands of small satellites that continuously hand off coverage to each other. Starlink (operated by SpaceX) and OneWeb are the two LEO constellations most relevant to commercial maritime operations in Southeast Asia today. MarineConnect supports both within our multi-WAN connectivity architecture, giving vessels access to whichever constellation delivers the strongest signal at any given moment.

How GEO Satellites Work -- and Where They Fall Short at Sea

Geostationary satellites have served maritime communications for decades, and they deserve credit for enabling VSAT (Very Small Aperture Terminal) connectivity when nothing else reached beyond coastal waters. A single GEO satellite can illuminate a vast footprint, covering an entire ocean basin. That is genuinely useful for wide-area coverage and for safety-grade services like GMDSS (the Global Maritime Distress and Safety System), which remains a mandatory ITU requirement under SOLAS Chapter IV for most commercial vessels.

The problem is latency. Because GEO satellites orbit at roughly 35,786 kilometres, the round-trip signal travel time is around 550 to 700 milliseconds under ideal conditions. For basic email, this is tolerable. For anything interactive -- a VoIP call, a video conference between a ship captain and a port agent, a remote desktop session for engine diagnostics -- 600ms of delay turns every exchange into an awkward shuffle of interruptions and silences.

There is also the congestion issue. GEO satellite capacity is divided across a beam shared by dozens or hundreds of vessels. In busy shipping corridors like the Straits of Malacca or near port hubs like Singapore and Ho Chi Minh City's Cai Mep terminal, vessels compete for bandwidth on the same beam. Speeds can drop sharply during peak anchorage hours. Rain fade -- signal degradation during heavy tropical downpours -- adds another reliability variable that fleet operators in Southeast Asia know well.

Why LEO Wins for Ships: Latency, Speed, and Real-World Performance

The performance difference is not marginal. GEO VSAT typically delivers latency of 550 to 700ms. A well-configured LEO connection via Starlink Maritime or OneWeb runs at roughly 20 to 40 milliseconds -- a 15 to 20x improvement that fundamentally changes what is possible onboard.

At 20 to 40ms latency, video calls work the way they do on shore. Bridge officers can join real-time fleet management sessions. Engine room IoT sensors report back to shore-based maintenance teams without perceptible delay. Seafarers in their cabins can stream video, make WhatsApp calls, or access banking apps during off hours, which matters more than ever given the strengthened crew welfare provisions under MLC 2006 and the ITF's push for guaranteed crew internet access.

Speed has also improved considerably. LEO constellations, particularly Starlink's Flat High Performance (FHP) antenna designed for maritime and mobile use, can deliver download speeds of 25 to 250 Mbps depending on conditions. That is more than enough to run parallel operational and crew networks without one starving the other. For vessels that previously budgeted data plans by the megabyte and rationed bandwidth like a scarce resource, the shift to LEO feels like a different category of service entirely.

Coverage continuity is another gain. LEO constellations are dense and satellites hand off seamlessly, so a well-managed LEO connection remains active mid-ocean in ways that individual GEO beams sometimes cannot match, particularly at the edge of a beam footprint or during beam transitions in Ka-Band GEO systems.

The Limitation LEO Alone Cannot Solve

LEO is a significant step forward, but it is not without failure modes -- and commercial shipping operators need to understand them before treating LEO as a complete solution.

The most common issue is physical obstruction. A Starlink phased-array dish needs a clear view of the sky. On a container vessel with towering crane structures at port, or a bulk carrier with deck equipment blocking the antenna's field of view, the signal can drop without warning. At busy anchorages, this happens more than vendors sometimes advertise.

There are also limitations at polar and high-latitude routes for certain LEO constellations, and service interruptions remain possible during severe weather or during constellation handoff windows. For vessels operating under ISM Code requirements where continuous bridge communication and operational data flow are mandatory, a LEO-only setup carries risk. A single point of failure is still a single point of failure, even if that failure is less frequent than before.

This is the architectural gap that smart maritime connectivity strategies are designed to fill. LEO is one layer -- an excellent layer -- but it performs best when backed by complementary networks that cover its weak moments.

How MarineConnect Combines LEO With Other Networks for Unbreakable Connectivity

At MarineConnect, our approach to vessel connectivity is built on the premise that no single satellite network -- LEO or GEO -- should be a vessel's sole connection to the world. The real breakthrough in maritime internet is not LEO itself; it is intelligent bonding of multiple networks so that the vessel always has a working path, regardless of what any individual link is doing.

Our multi-WAN management architecture integrates Starlink and OneWeb (LEO), GEO-VSAT, 5G/LTE coastal connections, and L-band (Fleet Broadband) into a unified onboard network managed by the SmartBox Gateway. The SmartBox acts as the central router and orchestrator, automatically selecting the best available path based on signal quality, latency, and traffic priority. If Starlink drops signal due to a crane obstruction at port, traffic shifts to GEO-VSAT or LTE within seconds -- no manual intervention, no dropped sessions.

For vessels using Inmarsat's NexusWave service, this bonding capability goes further through SD-WAN technology that keeps all underlays active simultaneously. Rather than switching between networks when one fails, NexusWave bonds them together, combining throughput and prioritising traffic across three segregated networks: Business (operational systems), OT (vessel operations and IoT sensors), and Crew (seafarer internet). Crew welfare connectivity does not compete with bridge navigation systems. Neither is sacrificed when demand spikes during port calls.

This is the architecture we deploy across fleets operating in the Singapore Strait, the South China Sea, and coastal Vietnamese waters. LEO provides the speed and low latency. The broader multi-WAN framework, managed through our Marine Connect services, provides the resilience.

Frequently Asked Questions

Is LEO satellite internet reliable enough for commercial vessels?

LEO internet, particularly via Starlink Maritime, has proven highly reliable in open-ocean conditions. That said, physical obstructions at port and occasional constellation handoff gaps mean that LEO alone should not be the sole connectivity link for a commercial vessel. The best practice is to use LEO as the primary high-speed layer within a multi-WAN setup that includes a GEO VSAT or LTE fallback. For vessels where continuous connectivity is a safety or operational requirement under SOLAS or the ISM Code, a redundant architecture is not optional.

What is the difference between Starlink Maritime and a GEO VSAT system?

The core differences are latency and antenna design. Starlink Maritime uses a phased-array antenna (the Flat High Performance dish) that actively tracks the LEO constellation across the sky, delivering latency of 20 to 40ms and speeds up to 250 Mbps. A traditional GEO VSAT system uses a gyro-stabilised dome antenna locked onto a single fixed satellite, delivering latency of 550 to 700ms. VSAT still offers more predictable contracted service-level agreements and remains preferred for GMDSS safety communications and some AIS-related regulatory reporting workflows.

Can LEO satellites cover Southeast Asian shipping routes fully?

Yes. Both Starlink and OneWeb provide coverage across the South China Sea, the Straits of Malacca, the Gulf of Thailand, and Vietnamese coastal and offshore waters. Coverage in these regions has matured significantly since 2023. Performance at high-demand anchorages -- particularly around Singapore, Port Klang, and Cai Mep -- can vary depending on local satellite load. Combining LEO with LTE or GEO backup remains a sensible approach for fleet operators across Southeast Asia.

Do I need to replace my existing GEO VSAT if I add Starlink?

Not necessarily. In a multi-WAN architecture, your existing VSAT becomes a fallback layer rather than the primary connection. Many operators we work with retain their VSAT for GMDSS compliance and as a reliability backup while adding Starlink as the primary high-speed link. The SmartBox Gateway manages both and decides in real time which to use, or bonds them together when bandwidth demands require it. You gain the LEO performance benefit without losing the VSAT safety net.

Ready to Move Beyond Legacy VSAT?

The shift from GEO to LEO is the most significant change in maritime connectivity in a generation. The vessels that get the most from it are not those that simply swap one antenna for another -- they are the ones that treat LEO as a powerful layer within a smarter, multi-network architecture.

MarineConnect is a Singapore-based maritime connectivity specialist supporting fleets across Southeast Asia. We deploy, manage, and optimise multi-WAN systems combining Starlink, OneWeb, GEO-VSAT, 5G/LTE, and L-band into a single, intelligently managed network tailored to each vessel's operational profile.

If your fleet is still running on legacy VSAT, or if you are evaluating how LEO fits into your connectivity strategy, we are happy to walk through the options. Reach out via our Marine Connect services page or contact us directly to discuss your fleet's needs.