How ships get internet: VSAT, Starlink and crew Wi-Fi explained

By StratPollen Studio · Updated 5 November 2026 · 4 min read

Ask any seafarer what matters most on board after pay and food, and many will say the internet. It's how crews keep in touch with home, follow the news and pass the time. Yet internet at sea still works very differently from internet on land.

This guide explains where a ship's connection comes from, why crew Wi-Fi can feel slow even on a well-equipped vessel, and what the rules now say about access.

No phone towers out there

Near the coast and in port, your phone can use ordinary mobile networks. Once a ship is a few tens of kilometres offshore, that signal is gone. From then on, everything comes through a satellite: email, ship's reports, chart updates, video calls home.

There are two main kinds of satellite service used at sea, and they behave very differently.

Geostationary satellites (VSAT)

For many years, the standard for merchant ships has been VSAT using geostationary satellites. These sit about 35,786 km above the equator and stay over the same spot on Earth. A stabilised dish on the ship locks on to one satellite and keeps pointing at it while the ship rolls and turns.

• The good: a handful of satellites cover almost every ocean, except the far north and south.
• The catch: the signal has to travel all the way up and back down, twice, for every exchange. That adds a delay (called latency) of around 600 milliseconds or more for each round trip.

Six-tenths of a second doesn't sound like much, but you feel it on a video call: people talk over each other, and conversations feel stilted. Web pages that need many round trips also load slowly, even when the download speed is decent.

Ships also carry smaller, slower satellite services that are mainly used for safety messages, ship's business and as a backup when the main link is down.

Low Earth orbit satellites (LEO)

Newer services such as Starlink and OneWeb use thousands of satellites in low Earth orbit, a few hundred kilometres up instead of tens of thousands. Because the distance is so much shorter, latency drops to roughly 20–60 milliseconds, close to a home broadband line, and speeds are usually much higher.

The trade-off is that a ship's antenna must hand over from one fast-moving satellite to the next all the time, so coverage depends on how complete the network is in that area. Many ships now use LEO as their main link and keep VSAT as a backup.

Why crew Wi-Fi can still feel slow

Even with a good satellite link, the connection in your cabin may disappoint. Common reasons:

• The link is shared. The ship's own traffic (reports, emails, chart and software updates, monitoring data) usually takes priority, and the rest is split among the whole crew.
• Data allowances. Many companies give each crew member a monthly allowance or vouchers, and some limit speed once you pass a threshold.
• Busy hours. Everyone goes online after meals and watch changes, so speeds drop at exactly the times you're free.
• Weather and blockages. Heavy rain can weaken some satellite signals, and masts, cranes or cargo can block the antenna on certain headings.
• Filters. Some ships block video streaming or large downloads to protect the shared link.

What the rules say

The Maritime Labour Convention (MLC 2006) was amended in 2022, and those changes came into force on 23 December 2024. One of them makes social connectivity part of the recreational facilities that shipowners must provide on board.

In practice, this means shipowners are expected to give crew internet access as far as is reasonably practicable, and any charges should be reasonable. The amendments also encourage port states to provide free or affordable internet in port areas. The exact details depend on the flag state and the company's own policy, so check your contract or ask your company what applies on your ship.

Getting the most from a ship's connection

• Turn off automatic updates and backups for apps and photos while on board. Do them in port on shore Wi-Fi instead.
• Go online at quiet times, such as the middle of a watch rather than right after dinner.
• Prefer text and voice notes to video when the link is slow. They arrive even when a call would keep dropping.
• Use low-data settings in your messaging apps, and stop media from downloading automatically.
• Download in advance. Films, music, maps and books can all be saved before you sail.

Our guide to saving data at sea and abroad covers phone settings step by step, and how much data messaging uses shows what each kind of message costs.

Quick takeaways

• Offshore, all internet comes by satellite.
• Geostationary links cover almost everywhere but add a noticeable delay; low-orbit links are much faster but rely on a big network.
• Crew Wi-Fi is shared, so habits and timing make a big difference.
• Since December 2024, the MLC expects shipowners to provide crew with social connectivity on board.