No visa is required for all nationalities, though all foreigners must have passport valid for at least 6 months, and must have proof of accommodation bookings before arrival. An initial entry permit is granted for 1 month but can be extended for a maximum of 3 months at a time up to a maximum of 1 year in total. See the official travel web-site (http://www.seychelles.tra...).
The strict controls imposed on cruising yachts in the early 1990s have been gradually lifted and rules and regulations are no longer so complicated. However, some restrictions remain in force, mostly for the sake of environmental protection as most of the islands are surrounded by coral reefs near the surface.