Ship types explained: AIS type codes and what they mean
· 3 min read
In short
Ships describe their own type over AIS with a two-digit code from 0 to 99, defined in Recommendation ITU-R M.1371. The first digit gives the broad class (6x passenger, 7x cargo, 8x tanker), and for most classes the second digit says whether the ship carries hazardous cargo. The codes are coarse: a container ship, a bulk carrier and a car carrier all report 70, “cargo”. That is why Voydar combines the AIS code with registry descriptions to place each ship in one of about 40 specific types.
The AIS ship-and-cargo type code
| Code | Meaning |
|---|---|
| 0 | Not available (the default) |
| 20–29 | Wing-in-ground craft |
| 30 | Fishing |
| 31, 32 | Towing; towing with a tow longer than 200 m or wider than 25 m |
| 33 | Dredging or underwater operations |
| 34 | Diving operations |
| 35 | Military operations |
| 36 | Sailing |
| 37 | Pleasure craft |
| 40–49 | High-speed craft |
| 50 | Pilot vessel |
| 51 | Search and rescue vessel |
| 52 | Tug |
| 53 | Port tender |
| 54 | Anti-pollution equipment |
| 55 | Law enforcement |
| 56, 57 | Spare, for local vessels |
| 58 | Medical transport |
| 59 | Non-combatant ship (under ITU Radio Regulations resolution 18) |
| 60–69 | Passenger ship |
| 70–79 | Cargo ship |
| 80–89 | Tanker |
| 90–99 | Other type |
The second digit: hazardous cargo
For wing-in-ground craft, high-speed craft, passenger ships, cargo ships, tankers and “other” types, the second digit adds cargo information. 0 means “all ships of this type”, 1 to 4 mean the ship carries dangerous goods, harmful substances or marine pollutants in one of four categories, 9 means “no additional information”, and 5 to 8 are reserved. Current AIS equipment labels them X, Y, Z and OS after the MARPOL categories; older equipment labels the same categories A, B, C and D, which is why you may see “Tanker (hazardous cat. A)”.
So code 80 is a tanker with no cargo category given, 81 a tanker carrying category X (or A) cargo, and 71 a cargo ship with category X (or A) cargo. Like the destination, this digit is entered by the crew and is not always kept up to date.
Why the AIS code is not enough
The code tells you whether a ship is a cargo ship or a tanker, but not which kind. The distinctions that matter commercially, such as container ship, bulk carrier, oil tanker, LNG carrier or cruise ship, are not in the code at all. The code is also typed in when the transponder is installed, so a converted ship can keep reporting its old type.
Voydar therefore keeps two layers. The AIS code is shown as the ship reports it. Separately, Voydar maps each ship to one of about 40 canonical types using registry descriptions (for example from Wikidata) as well as the AIS code, and each canonical type has its own page with the fleet, the largest ships and where they are now.
Browse ships by type
Voydar’s type pages combine the AIS code with registry descriptions, so a container ship is not just “cargo”.
- Cargo ships · Container ships, Bulk carriers, General cargo ships
- Tankers · Oil tankers, Chemical tankers, LNG carriers
- Passenger ships · Cruise ships, River cruise ships, Ocean liners
- High-speed craft
- Fishing vessels
- Tugs
- Offshore supply vessels
- Offshore units
- Dredgers
- Pilot vessels
- Search and rescue vessels
- Law enforcement vessels
- Naval vessels
- Research vessels
- Icebreakers
- Cable and pipe layers
- Crane vessels
- Diving support vessels
- Port tenders
- Anti-pollution vessels
- Medical vessels
- Salvage ships
- Pleasure craft
- Sailing vessels
- Training ships
- Museum ships
- Wing-in-ground craft
Types and sizes
Shipping also sorts ships by size class, such as Handysize, Panamax, Suezmax or VLCC for tankers and bulk carriers. Those classes are industry conventions based on deadweight or on the canals and ports a ship fits, not official categories, and definitions vary between sources. For how ship size is measured, see gross tonnage vs deadweight.
Questions and answers
- What is AIS ship type 70?
- A cargo ship, with no hazardous-cargo category given (“all ships of this type”). It covers container ships, bulk carriers, general cargo ships and car carriers alike.
- What does “hazardous category A” mean on a ship?
- That the crew has set the AIS type’s second digit to 1: carrying dangerous goods, harmful substances or marine pollutants of MARPOL category X, shown as A on older equipment.
- Why does a yacht show as type 0?
- 0 means the type was never set. It is common on small-craft transponders.
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.
- ITU-R M.1371: Technical characteristics for an automatic identification system
- U.S. Coast Guard Navigation Center: AIS static and voyage data (message 5)
- IMO resolution A.1106(29): hazardous cargo categories on older AIS equipment
Published Sep 28, 2026 · For information only. Not for navigation, and not a substitute for the official sources cited.