While diving holds center stage in Chuuk, snorkelers can visit more than 15 shallow WWII wrecks and submerged planes too! The sheltered lagoon cuts down on the Pacific’s waves and currents, which makes for relaxed exploring. Stretching 64 kilometers (40 miles) in diameter, it has a wealth of unmapped reefs. Expect to see some of the ocean’s healthiest corals, alongside turtles, dolphins and schools of tuna. Note: You won't need a wet suit for warmth (the water is a balmy 27 to 30 degrees Celsius, or 80 to 86 degrees Fahrenheit year round), but the sun is so strong that a UV-protection rash guard or 1mm wet suit is still recommended for your surface adventures.