Waikiki Aquarium

The Waikiki Aquarium sits on the shoreline at Kapiolani Park, a short walk from the hotels, and has been a favorite since 1904. It is run by the University of Hawaii, so the focus is science and conservation: Hawaiian reef fish, corals, sharks, jellyfish, the chambered nautilus and the endangered Hawaiian monk seal. It is small, easy and affordable, and makes a good rainy-day or pre-snorkel stop, especially for families who want to identify the creatures they will see in the ocean.

Few aquariums are as well placed. The Waikiki Aquarium looks over the reef it showcases, and many exhibits draw on the waters just outside its doors. Founded in 1904, it ranks among the oldest public aquariums in the country, and its association with the University of Hawaii gives it a research and education role.

Displays walk through habitats from tidal pools to deep reef, with an emphasis on species native to Hawaii and the broader Pacific.\n\nHighlights include the live coral exhibits, which show how reefs grow and why they matter; the shark tank; the jellyfish; and the chambered nautilus, a living fossil rarely seen in aquariums.

Outdoors, Hawaiian monk seals, among the most endangered seals in the world, rest in a habitat that lets visitors learn about their biology and recovery programs. Interactive displays and signage cover Hawaiian names, cultural uses and conservation topics, which will help you recognize species when you snorkel at Hanauma Bay or Turtle Canyon.

\n\nThe visit takes one to two hours, and the compact layout suits young children. Entry is inexpensive compared with larger attractions, and check the schedule for talks and feedings. The aquarium is next to Kapiolani Park, the Honolulu Zoo and the Waikiki Shell, so you can build an afternoon around them. Bring sun protection for the outdoor sections, and confirm opening hours before you go. It is a good low-key complement to the more adventurous activities on Oahu.

A good strategy is to visit before a snorkel day, so you can match the fish on the labels to the ones you will see in the water, then come back afterward to check what you spotted. Children enjoy hunting for the species that appear on the identification cards, and staff are generally happy to answer questions about reef etiquette and conservation.