Lagos is surrounded by water, and the escape routes are better than most residents realise. An hour east puts you in Epe's lagoon resorts; an hour west is Badagry; a twenty-minute boat ride from Victoria Island reaches private beaches with nobody on them.
This guide covers both day trips and overnight stays, with honest travel times — the drive is almost always the hardest part.
For beaches you can reach without a resort gate, see the best beaches in Lagos.
