A different Hawaii greets anyone with a mask, snorkel, and fins. Under the sea, you'll find schools of brilliant tropical fish, slow-moving green sea turtles, darting game fish, slack-jawed moray eels, and prehistoric-looking coral. It's a kaleidoscope of color and wonder.
- Hanauma Bay: It can get very crowded, but — for clear, warm, calm waters, an abundance of fish that are so friendly, they'll swim right up to your face mask, a beautiful setting, and easy access — there's no place like Hanauma Bay. Just wade in waist-deep and look down to see more than 50 species of reef and inshore fish common to Hawaiian waters. Snorkelers hug the safe, shallow inner bay — it's really like swimming in an outdoor aquarium. Serious, experienced divers shoot "the slot," a passage through the reef, to gain access to Witch's Brew, a turbulent cove, and other outer-reef experiences.
- Wreck of the Mahi: Oahu is a wonderful place to scuba dive, especially for those interested in wreck diving. One of the more famous wrecks in Hawaii is the Mahi, a 185-foot former minesweeper, which is easily accessible just south of Waianae. Abundant marine life makes it a great place to shoot photos — schools of lemon butterflyfish and ta'ape are so comfortable with divers and photographers that they practically pose. Eagle rays, green sea turtles, manta rays, and white-tipped sharks occasionally cruise by, and eels peek out from the wreck.
- Kahuna Canyon: One of the most magical summer dive spots is Kahuna Canyon. Walls rise from the ocean floor to create the illusion of an underwater Grand Canyon. Inside the canyon, crab, octopi, slipper, and spiny lobsters abound (be aware that taking them in the summer is illegal), and giant trevally, parrotfish, and unicorn tangs congregate. Outside, you're likely to see the occasional shark in the distance.
- Shark's Cove: Braver snorkelers might want to head to Shark's Cove, on the North Shore just off Kamehameha Highway, between Haleiwa and Pupukea. Sounds risky, we know, but we've never seen or heard of any sharks in this cove; and in summer, this big, lava-edged pool is one of Oahu's best snorkeling spots. Waves splash over the natural lava grotto and cascade like waterfalls into the pool full of tropical fish. Deep-sea caves to explore are to the right of the cove.
- Kapiolani Park Beach: The section known as Queen's Beach or Queen's Surf Beach in the center of this beach park, between the Natatorium and the Waikiki Aquarium, is great for snorkeling. That said, we prefer the reef in front of the Aquarium because it has easy access to the sandy shoreline and the waters are usually calm. Bonus: Since you're right next door to the Aquarium, if you see any flora or fauna and would like more information, you can pop inside.