Can I track a ship for free?

Yes. Looking up any ship on Voydar, with its last position, identity, owner and port calls, is free and needs no account. A free account adds following up to 5 ships and ports with email alerts.

How do I track a ship by its MMSI?

Type the nine-digit MMSI into the search box. The MMSI is the number of the ship's radio and is sent in every AIS message, but it can change when a ship changes flag, so for a long-term record use the IMO number as well.

Why can't I find a ship?

Either the name or number is not exactly right, or the ship does not transmit AIS, or no receiver has heard it. Warships and many small boats do not carry AIS, and a ship far from any coast may not have been heard for days.

Is the position live?

It is the latest position a receiver passed on. Where coverage is good that is within seconds or minutes. Where it is not, the page shows the age of the last position so you can judge it.

How to track a ship

Updated Oct 5, 2026 · 4 min read

In short

To track a ship, search for it by name, IMO number or MMSI on a vessel-tracking site and open its page. You get its last position from AIS, the time that position was received, its speed and course, and the destination its crew entered. The IMO number (seven digits) and the MMSI (nine digits) find exactly one ship, while a name alone can match several. A position is only as fresh as the last signal a receiver heard, so check its age before you rely on it.

Find the ship

With an IMO number or MMSI: type it into the search box on the Voydar home page. An IMO number belongs to one hull for life and an MMSI is the number of its radio, so either one finds a single ship. The two are not the same thing: see IMO number vs MMSI.
With only a name: search the name and pick the right ship from the results by its type, flag and IMO number, because many ships share a name.
From a link: a vessel page has the address voydar.com/vessel/ followed by the IMO number, so a ship you know by its IMO number can be opened directly.

Once you have the ship's page, the first thing to read is the position and the time it was received.

Read the position, and its age

A vessel page shows the last AIS position it has for the ship, the area, the speed, the course and the navigational status, and states when that position was received. The age matters more than the dot: a position received a few minutes ago is where the ship is, one received days ago is only where it was.

The destination and the ETA on the page are typed in by the crew, not measured, and are often out of date or written in free text. Treat them as the ship's own statement of intent. How ship tracking works explains why.

When a ship has gone quiet

A ship that stops appearing has usually left radio range: AIS is received by shore stations, other ships and satellites, and coverage is thin far from the coast. It does not normally mean the ship switched its transponder off.

For a ship that was clearly under way and has not been heard for six hours or more, the Voydar vessel page can add an estimate of where the ship would be if it had held its course and speed. It is labelled as an estimate, shows an uncertainty radius that grows with the distance run, and stops after 36 hours, when it says the last position is too old to estimate from.

To be told when a quiet ship is heard again, follow it. A free account follows up to 5 ships and ports, Plus 50 and Pro 500, and the first email arrives when the ship is next heard, then when it reaches or leaves a port.

Tracking more than one ship

The live map shows ships as they move and opens any of them on a click. A port page lists the ships arriving and leaving, and the cruise ship tracker shows where each cruise ship is now by cruise line. The Voydar news page lists ships named in recent reports, each with its page.

Which ships can appear at all depends on who transmits AIS: ships over 300 gross tonnage on international voyages, all passenger ships and many smaller boats do, while warships and many small craft do not. See what AIS is for who has to carry it.

Questions and answers

Can I track a ship for free?: Yes. Looking up any ship on Voydar, with its last position, identity, owner and port calls, is free and needs no account. A free account adds following up to 5 ships and ports with email alerts.
How do I track a ship by its MMSI?: Type the nine-digit MMSI into the search box. The MMSI is the number of the ship's radio and is sent in every AIS message, but it can change when a ship changes flag, so for a long-term record use the IMO number as well.
Why can't I find a ship?: Either the name or number is not exactly right, or the ship does not transmit AIS, or no receiver has heard it. Warships and many small boats do not carry AIS, and a ship far from any coast may not have been heard for days.
Is the position live?: It is the latest position a receiver passed on. Where coverage is good that is within seconds or minutes. Where it is not, the page shows the age of the last position so you can judge it.

Try it

Put this guide to work with a free Voydar tool, no account needed.

Look up a ship

Search any vessel by name, IMO number or MMSI for its free Voydar profile: live position, identity history, ownership, inspections and sanctions.

Sources

Primary sources for the facts in this guide. Figures labelled as Voydar data come from Voydar’s own records, with their method stated next to them.

Published Oct 5, 2026 · For information only. Not for navigation, and not a substitute for the official sources cited.