Spooky St John's has a chequered past: it was a quarantine station for immigrants in the 1930s before becoming a political prison and later a rehabilitation centre for opium addicts. A prison-like feel still lingers – barbed-wire fences and watchtowers dot the landscape and you'll see plenty of 'do not enter' signs. There's a small beach that some families use for picnicking, and a tiny tin-roofed mosque used by maintenance workers, but most visitors head here for a quiet spot of fishing.
The island has one self-contained, three-bedroom bungalow. Camping is not allowed on St John's, although some people occasionally flout the rules.