Regular members are (deputy) directors of stations, laboratories, institutes, or university departments primarily devoted to fundamental marine science and possessing coastal research facilities. There are maximally 7 regular Board members. The President and Executive Secretary send every 2 years invitations for nominations to all MARS members. The acting Board members select new regular members from the nominees.
Co-opted members are appointed for specific reasons, and are proposed by the regular members of the Executive Board. Maximally 4 co-opted members can be appointed on the basis of being: 1) Executive Secretary, leading the Executive Office and administration, established at the seat of MARS, 2) Executive editor of the Newsletter, 3) co-ordinator of a major MARS related scientific project, 4) linked to an organisation relevant to the aims of MARS, as being member of a marine committee in e.g. UNESCO or the EC Parliament. Co-opted members have, once invited, the same rights and duties as the regular members of the steering committee.
Honorary members have received the MARS medal of Honour because of their merits and outstanding reputation in marine science.