But more adventurous nature lovers are heading for the South Pacific kingdom of Tonga, where you can actually swim with some of the world's largest mammals.
Whaleswim Adventures, tel: (64-9) 372 7073, run six-, seven- and nine-day tours that feature opportunities to swim with humpback whales off the island of Vaka'eitu, near Vava'u in Tonga's north. To minimize environmental impact, each tour has a limit of 12 people, of whom only four (plus a qualified marine researcher-cum-guide) are allowed in the water at any one time.
Between July and October every year, humpbacks migrate from Antarctica to the 171-island archipelago to give birth and nurse their calves—and Whaleswim tours make straight for the nurseries. "It's a truly life-changing experience to watch a young, 12-m calf suckling its 40-m mother just meters away," says Rae Gill, Whaleswim's tour director. "The trust these wild animals have in us is humbling in itself. I know of no other wild animals that allow this." Tours start from $1,752.