Membership in the Salem Marine Society was open only to captains at first, then in 1790 to ship owners as well. When a gentleman was accepted as a member, the certificate would be filled out with his membership number, name, and date, then signed by the Secretary and Master of the society. Finally, a red wax seal would be fixed to the bottom of the certificate.

Members would pay dues, and fines for such offences as quarreling with other members, using foul language in a meeting, or missing a meeting. The fines and dues would be kept by the society and used for their charitable or navigational activities.