It is decisive whether the person works on board a ship with functions related to the ship and where this work is done, i.e. either at sea or in port.
Seafarers are, inter alia, persons who have been employed by a shipowner to do ship service on board a ship at sea, i.e. work performed by persons taking part in the ship's operation and maintenance as well as the provisioning of those on board. Furthermore, seafarers can be persons who perform repair and maintenance work on ships, special ship personnel who have been engaged to work at sea on board a ship as well as cleaning and catering personnel.
Certain categories of persons on ships with a land-based employment are not considered as seafarers when they do not perform work as described above. The following persons are for example not categorized as seafarers: offshore specialists, journalists, researchers, co-operating shipping companies, co-operating craftsmen and service technicians.
However, the persons are subject to minimum protection, which entitles the persons to rest periods and care, and in certain cases the right to return with maintenance, the right to resignation and the right to compensation for property. In some cases they are required health certificates and basic training.
Persons who is not covered by the definitions above are not seafarers but passengers. This means that you are not required to have an employment contract for seafarers, are not covered by the rules on rest periods and do not need a health certificate.
If in doubt whether a person is a seafarer, please contact the Danish Maritime Authority.