Snorkeling is the easiest ocean sport available on the island, requiring nothing but a snorkel, mask, fins, and good sense. Borrow equipment from your hotel or purchase some in Lanai City if you didn't bring your own. Wait to enter the water until you are sure no big sets of waves are coming; and observe the activity of locals on the beach. If little kids are playing in the shore break, it's usually safe to enter. To get into the water safely, always swim in past the breakers, and in the comparative calm put on your fins, then mask and snorkel.
Hulopoe Beach is an outstanding snorkeling destination. The bay is a State of Hawaii Marine Conservation District and no spearfishing or diving is allowed. Schools of manini(sergeant major fish) feeding on the coral coat the rocks with flashing silver, and you can view kala(unicorn fish), uhu(parrot fish), and papio(small trevally) in all their rainbow colors. As you wade in from the sandy beach, the best snorkeling is toward the left. Beware of rocks and surging waves. When the resident spinner dolphins are in the bay, it's courteous to watch them from the shore. If swimmers and snorkelers go out, the dolphins may leave and be deprived of their necessary resting place. Another wade-in snorkel spot is just beyond the break wall at Manele Small Boat Harbor. Enter over the rocks, just past the boat ramp. It's dangerous to enter if waves are breaking.
Trilogy Oceansports Lanai. A 4½-hour blue-water snorkeling and adventure catamaran trip explores Lanai's pristine coastline with Trilogy's experienced captain and crew. The trip includes lessons, equipment, and deluxe lunch served onboard. Tours are offered Monday, Wednesday, Friday, and Saturday; cost is $181 for adults and $90 for kids 15 and under. You can book trips through your hotel concierge, but try online first, where discounts are often available. 888/628-4800. www.sailtrilogy.com.