The Marine Conservation Society Seychelles (MCSS) is a Non-Governmental Organisation registered in Seychelles which promotes the conservation of the marine environment through education, research and the implementation of a number of programmes. Current activities include long-running monitoring programmes on turtles and terrapins, coral restoration as well as several grant-funded programmes and projects.

Most of their projects are supported by volunteer effort and several are funded through sponsorship by local businesses, associations and individuals.