Honolulu

Waikiki’s longest-running catamaran, sailing since 1977 and launching straight off the sand in front of Duke’s, between the Royal Hawaiian and the Outrigger Waikiki. The day sail is a single hour out toward Diamond Head and back under sail, which is about the right length for small children and costs less than most Hawaii activities. There is no minimum age and boarding is a walk down the beach rather than a harbor check-in, so it works as a spur-of-the-moment outing on a beach day. This is the cheapest way to get a family onto a sailboat in Hawaii.

A 44-foot catamaran that launches off the sand behind the Sheraton Waikiki and sails the water directly in front of Waikiki with Diamond Head off the stern. The operator’s own description is that the wind and waves are the engine, and it has a reputation among Waikiki boats for actually hoisting sail. The 11am and 1pm Tradewind sails are the family slot and the cheapest; the later afternoon and sunset departures are built around an open bar and cost more. Children under 3 sail free and there is a child rate through age 12.

The battleship where Japan formally surrendered in 1945, moored on Ford Island and open to walk through from the teak deck down into the ships interior. Kids stand on the surrender deck, sit in the wardroom, climb up to the bridge and look down the sixteen-inch gun barrels. Guided tours go below into crew quarters and the engine spaces. Large parts are enclosed which makes it workable in rain, though the main deck is open. Reached by the Ford Island shuttle from the Pearl Harbor visitor center.

The state museum of Hawaiian history and natural science, and the first thing to reach for when a beach day on Oahu gets rained out. Hawaiian Hall is three koa-wood galleries of chiefly regalia, feather capes and a whale hanging from the ceiling. The Science Adventure Center has a walk-through volcano with a lava-flow demonstration that erupts on a schedule and genuinely startles kids. There is a planetarium running Polynesian wayfinding shows about how navigators crossed the Pacific by stars. Plan three hours and check the daily schedule of hula and science demonstrations on arrival.

Oahus childrens museum in Kakaako, with four themed galleries built for hands-on play rather than looking. Kids run a mini television studio, work in a pretend supermarket and fire station, and explore Fantastic You where they walk through an oversized model of the human body. Rainbow World covers cultures across the Pacific with costumes and homes kids can go inside. It is aimed squarely at the under-tens and is the best wet-weather option on the island for that age. Two to three hours and a short drive from Waikiki.

Free admission, air conditioning and contemporary Hawaii art in a historic Spanish Mission style building downtown, which is a good combination on a wet Honolulu afternoon. The collection is entirely by artists connected to Hawaii and skews colourful and accessible rather than difficult. There is a dedicated hands-on family gallery where kids can make art and use activity kits. Because it is free you can walk in for twenty minutes and leave without guilt. Sculpture garden outside for when the rain lets up.

A beautiful low-slung museum built around a series of open courtyards, which makes it feel airy rather than institutional even in the rain. The Asian art collection is one of the strongest in the country and the Japanese and Chinese galleries have armour, screens and ceramics that kids react to immediately. Family art activities run on select weekends and children are admitted free. The cafe in the courtyard is genuinely good, which matters when you are killing a wet afternoon. An hour and a half is plenty with kids.

The only royal palace on American soil, home of Hawaiis last monarchs and a genuinely moving place to bring older kids. Guided and audio tours take you through the throne room, the grand staircase and the upstairs room where Queen Liliuokalani was imprisoned after the overthrow. The palace had electric light and telephones before the White House did, which is the detail kids remember. Everyone wears booties over their shoes to protect the koa floors. Tours run on a schedule so book ahead, and note it is not a place for restless toddlers.

Two working seaplane hangars on Ford Island that still carry bullet holes from December 7, 1941, filled with restored aircraft from that day forward. Kids see a Japanese Zero, a B-25 bomber and Cold War jets up close, plus a restoration shop where volunteers work on planes in view. Flight simulators let older kids fly a mission and are usually an extra ticket. The setting does most of the work here because you are standing inside the actual buildings. Reached by shuttle bus from the Pearl Harbor visitor center.

A real World War II submarine you go down inside and walk through end to end, which is the kind of thing kids talk about for years. The passages are genuinely tight, the bunks are stacked beside torpedoes, and an audio tour explains what life aboard was actually like. An adjoining indoor museum holds torpedoes, a Poseidon missile and submarine artifacts. It is at the Pearl Harbor visitor center so it slots in alongside the memorial and aviation museum. Not suitable for strollers and small kids need to manage steep ladders.

A small aquarium right on the Waikiki shoreline focused entirely on Pacific and Hawaiian reef life, which means kids see the same fish they might snorkel with an hour later. Hawaiian monk seals live in an outdoor habitat and are the highlight for most children. There is a giant clam collection, a jellyfish gallery and a shallow outdoor touch tank. The whole visit runs about an hour and it is walkable from most Waikiki hotels, which makes it an easy rainy-morning pivot. Partly open air, so a poncho helps in a real downpour.

The most iconic hike on Oahu and probably all of Hawaii. The 1.6-mile round trip trail climbs inside the crater of this famous volcanic tuff cone to the summit for panoramic views of Waikiki, the Pacific Ocean, and the Koolau Mountains. Kids love the tunnel, bunker, and steep staircase near the top that add adventure to the climb. The trail is paved but steep in sections. Reservations are required and the earlier you go the better to beat the heat and crowds.

A protected marine bay set inside a volcanic crater with the best easy snorkeling on Oahu. The reef is teeming with colorful fish that swim right up to you in shallow water. Kids are mesmerized from the moment they put their face in. A mandatory short educational video before entry teaches kids about reef conservation which makes the experience more meaningful. The beach is sandy with a gentle slope into calm turquoise water. Arrive early because the parking lot fills fast and the preserve caps daily visitors.

A staircase of 1048 old railway ties straight up the side of Koko Crater to the rim at 1,208 feet. This is essentially a giant outdoor stairmaster and kids who are up for the challenge love the sense of accomplishment at the top. The views from the rim are panoramic covering Hanauma Bay, Sandy Beach, and the east side of Oahu. The climb is relentless with no shade so start early and bring lots of water. There is a gap in the ties about two-thirds up where a bridge once stood that requires some scrambling.

A lush rainforest hike just 15 minutes from Waikiki that ends at a beautiful 150-foot waterfall. The 1.6-mile round trip trail winds through a tropical jungle with massive banyan trees, bamboo groves, and wild ginger. Kids feel like they have entered a movie set and in fact many films have been shot here. The trail can be muddy so sturdy shoes are essential. The waterfall at the end drops into a rocky pool surrounded by greenery. Swimming in the pool is discouraged due to bacteria but the view is stunning.

The most famous beach in Hawaii and still one of the best for families. The water is calm and warm, the sandy bottom slopes gently, and beginner surf lessons are available all along the shore. Kids can build sand castles, take a catamaran cruise, or try stand-up paddleboarding. The beach is backed by hotels and shops so everything you need is within walking distance. Lifeguards are on duty and the Duke Kahanamoku statue makes a great photo spot. Yes it is touristy but kids do not care about that.