The open ocean looks empty, but it's crisscrossed by tens of thousands of ships at any moment — and most of them are broadcasting exactly where they are. Whether it's the cruise your family is sailing on, the container ship carrying your online orders, or a tugboat in your local harbor, you can follow almost any vessel in real time.
How ships broadcast themselves
The maritime equivalent of a plane's transponder is AIS — the Automatic Identification System. Ships continuously transmit their unique ID, name, position, speed, heading and destination so that vessels can see and avoid one another at sea. Coastal receivers and satellites collect all that data, which is what lets a tracking map show the world's shipping live. International rules require AIS on most large vessels — cargo ships over a certain size and effectively all passenger ships — so the big ones are almost always visible.
Tracking a cruise ship
This is the one most people want. Search a cruise ship by name and you can watch its live position, speed and next port of call. It's perfect for following along when friends or family are aboard, checking whether a ship will make port on time, or simply daydreaming over where the great liners are right now.
Tracking cargo and the supply chain
The workhorses of the sea are just as fascinating. You can follow container ships, oil tankers and bulk carriers across the oceans, watch them stack up waiting for a berth outside major ports, and spot the sheer giants — the largest container ships now carry over 20,000 containers at once. It's the hidden machinery of the global economy, visible on a map.
What AIS tells you about a ship
- Name and vessel type (cruise, cargo, tanker, tug, ferry)
- Live position, speed and heading
- Origin and destination port, often with an ETA
- Size and, frequently, the ship's flag and details
The ships that go dark
Not everything shows up. Naval and military vessels routinely switch their AIS off for security, so warships often vanish from the map; some fishing boats stay quiet about their favorite spots too. Those gaps are part of the intrigue — most of the sea is an open book, with a few deliberate blanks.
Fun things to track
Once you start, it's hard to stop. Follow historic tall ships on a race leg, watch a mega-yacht cruise the Mediterranean, track the world's biggest container ships, or find the research vessels and icebreakers working the polar seas. The water turns out to be every bit as busy — and every bit as trackable — as the sky.
Quick answers
Is tracking ships legal and free to view? Yes. AIS is a public maritime-safety broadcast designed to prevent collisions, and vessel positions within receiver range are openly viewable.
Why can't I find a specific ship? A few reasons: it may have switched AIS off (common for naval vessels), it may be in the middle of an ocean beyond shore-based receivers (satellite AIS helps here), or it may be a small craft that isn't required to carry AIS.
Can I track a cruise ship I'm not on? Absolutely — just search the ship by name to see its live position, speed and next port, which is great for following friends or family aboard.
How live is the data? Within coverage it's close to real time, refreshing as the ship transmits — typically every few seconds to a couple of minutes depending on speed.
