A golden arc on the eastern rim of the Inhambane panhandle, a couple of degrees south of the Tropic of Capricorn, Mozambique's Praia do Tofo seems like the ideal place to laze in the sun. But speak to the locals and you'll soon discover that there is cause to leave the lounge chairs set out by the rapidly growing number of luxury hotels. The reason: whale sharks, a veritable posse of them, cruising in a corridor of nutrient-rich water less than a mile offshore.

Found in warm waters from Tanzania to Taiwan, the world's biggest fish has spawned a mini-industry full of outfitters promising access to the docile giants. Even compared with more popular whale shark tourism destinations, including Mexico's Whale Shark Biosphere Reserve and the Coral Sea, Tofo is exceptional. Research by conservation biologist Simon Pierce shows that daily "ocean safari" excursions out of Tofo find sharks 87 percent of the time. Sign up, haul the rigid inflatable through Tofo's tumble-dryer surf, slither aboard, and, chances are, your run-in with a goliath is just moments away.

"There aren't many places where sightings are virtually predictable," says Dr. Pierce, a New Zealand native whose interest in whale sharks drew him to Mozambique in 2005. "That's what makes Tofo such a hot spot."

After swimmers climb aboard the shark-seeking vessels, the pilot guns through the swells while a spotter crouched atop a scaffold in the stern keeps watch for fins. A guide offers a simple warning for first timers: "Don't swim in front of it and, whatever you do, don't touch!"

Unless you're part of the unlucky 13 percent, someone will spot a fin – several perhaps – and chaos will ensue as hyper-excited tourists don snorkels, swivel on the rubber, and hurl themselves into the ocean. When the first few frantic moments have passed and everyone has found a point at which they can admire the creature without getting kicked or inadvertently swallowed, all that's left is to watch the sharks swim gracefully through the blue.

More information: Daily flights to Inhambane Airport are available from Johannesburg and Maputo aboard Mozambique Airlines. Lovely rooms with ocean views are available for $140 a night at Blue Footprints, which can arrange whale shark tours with a number of local outfitters.