Tinderbox Marine Reserve (parks.tas.gov.au; free) borders a small beach in the delightfully named Tinderbox, near Blackmans Bay about 23km south of Hobart. Strap on a snorkel and follow an underwater trail running alongside a sandstone reef not far offshore, which is marked with submerged information plates explaining the rich local ecosystem (although these are now somewhat hard to read). There are usually plenty of fish here – wrasse, leatherjackets, seahorses and crayfish.