Hawaii is one of the world's most popular destinations for ocean kayaking. Beginners can paddle across a tropical lagoon to two uninhabited islets off Lanikai Beach on Oahu, while more experienced kayakers can take on Kauai's awesome Na Pali Coast. In summer, experts take advantage of the usually flat conditions on the north shore of Molokai, where the sea cliffs are the steepest on earth and the remote valleys can be reached only by sea.