A passenger-kilometre (pkm) is a unit of measurement used to describe the passenger capacity of a vehicle, such as a taxi or a bus. Passenger-kilometres are calculated by multiplying the distance travelled by the number of passengers carried. For example, a distance of 100 kilometres travelled by three people amounts to 300 passenger-kilometres.
Fast ferries include hydrofoils operating for example between Helsinki and Tallinn.
Ro-Pax vessels (roll-on/roll-off-passenger vessels) carry both passengers and cargo. Ro-Pax ships operate for example between Finland and Germany.