The lack of running water on Lehua and Niihau keep the waters around Lehua clean and clear. It is rare that visibility is less than 70 feet. If it is less, it is because of plankton and not silt so we’ll find an even greater number and variety of reef fish feeding at these times.
Lehua is a small, crescent-shaped island only 0.7 miles (1.1 km) North of Ni’ihau. The uninhabited, 284-acre (1.15 km²) island is a tuff cone that is part of the extinct Ni’ihau volcano.
Lehua Island is a Hawaii State Seabird Sanctuary. As a sanctuary, many activities are prohibited on the island, but entry is not prohibited. Lehua provides habitat for at least 16 species of sea birds, as well as some non-native rats. Rabbits were formerly a problem, being responsible for the destruction of the native vegetation on the island and suspected of eating bird eggs and baby birds during the dry season, which is the nesting season for most of the sea birds. In 2006, Hawaii’s Department of Land & Natural Resources took steps to eradicate the rabbits which has thus far been successful.
When weather and wave conditions permit crossings from Kauai, Lehua is a noted destination for snorkeling and scuba diving. It is also well known for its unusual geological formation dubbed “the keyhole”. Located in one of the crescent’s narrow arms, this tall, thin notch cut reaches all the way through to the other side of the arm and makes for a terrific photo opportunity.
The United States Coast Guard maintains Lehua Rock Light on the highest point of the island, at a height of 704 feet (215 m).