Tortuguero National Park on Costa Rica's Caribbean coast is a protected wilderness area of mangrove swamp, lagoons and creeks, and also one of the best places on the continent for wildlife spotting. It is here, beneath a waning moon, that leatherback, green and olive ridley turtles arrive en masse to lay their eggs on the beach where they will incubate for several weeks in the warm sand. You will need a guide to visit the beaches at night (to protect the infants, no one is allowed on the beach unaccompanied after 6pm). Even luckier visitors can see the baby turtles finally emerge from their sandy cocoons in the late summer and make their way, clumsily, towards the uncertainty of the sea.
The Galápagos Islands, with their fearless crowds of sealions, iguanas, giant tortoises and exotic birds, offer all manner of opportunities to get well and truly up close to wildlife, but none more thrilling than the chance to dive with hundreds of hammerheads. The protected sharks, with their distinctive T-shaped heads, can be found there in abundance, and like the rest of the islands' creatures are more than happy to go about their business undisturbed by the presence of humans. Witnessing this astounding theatre of sea life for yourself is one of the greatest privileges that travel can grant, and hammerheads are far from its only performers – the convergence of cold currents from Antarctica and warm waters from the tropics creates microclimates to suit a mind-bending range of underwater species. Sea lions, rays, tropical fish, eels and sea turtles are easily spotted, while on land the unique conditions are characterised by penguins living just metres away from tropical pink flamingos.
Little laid-back, Caribbean Belize is home to a hotbed of underwater activity, from coral reefs teeming with colourful fish to divers exploring the far reaches of the cavernous Blue Hole. One of the easiest ways to get up close to Belize's lively sea life is to join a boat trip to Shark Ray Alley, near both Caye Caulker and Ambergris Caye. Local fisherman were the first to notice the huge congregations of nurse sharks and stingrays that had begun to frequent a narrow strip of the reef where the men would clean off their catch at the end of each day, and the area soon became a popular dive site. And while jumping into a clear turquoise sea filled with shark-shaped shadows, armed only with a snorkel and mask takes a little courage, in reality there's not much to be afraid of: the seemingly fearsome sharks don't even have any teeth!
Between May and September in Holbox, Mexico, and Placencia, Belize, it is possible to take to the seas in the company of the magnificent whale shark, the world's largest fish. Communing with the placid underwater giants is a privilege that is unlikely to be forgotten in a hurry: they can measure up to 12m in length. Feeling tiny in comparison, and surrounded by endless ocean, you cannot help but be struck by nature's grandeur and left well and truly awed by the experience.