Great Adventure Cruises
Courtesy of Coral Princess Cruises
Great Barrier Reef
The best snorkeling and diving lies beyond the reach of day-trippers from Australia’s mainland. But hop aboard a four-night cruise from Cairns with Coral Princess II, and you get to visit far-flung ribbon reefs and Lizard Island, where you’ll have a cove filled with giant clams to yourselves. coralprincess.com.au; from $1,946 per person.