Swimmers are set to bare all for conservation and self-acceptance on Sunday.

However, their costumes will only be removed once they run from the beach into the water and no stickybeaking is allowed.

Cheeky dip: Swimmers set out on the Sydney Skinny, the world's first nude ocean swim, last year. Credit:Janie Barrett

The Sydney Skinny, a nude ocean swim in its second year, is a private ticket-only event at the secluded Cobblers Beach in Mosman, on Sydney's lower north shore, from 8am.

Only participating swimmers are allowed on the beach and spectators are not allowed.