What's the must-see thing in Honolulu?

The USS Arizona Memorial sits at 1 Arizona Memorial Place in Pearl Harbor, about 30 minutes by car from Waikiki. The National Park Service runs a 75-minute program. First a 23-minute documentary, then a short boat ride to the memorial structure that spans the sunken battleship. Through the open sides you can see the rusted hull sitting in roughly 12 meters of water, and on calm days the oil that has been leaking since December 7, 1941 forms small rainbow slicks on the surface. That slow leak, still going after 84 years, tends to be the moment the visit stops feeling like a museum and starts feeling like a grave. Free admission, but you need a timed ticket from recreation.gov. They release slots 60 days in advance and sell out fast. Walk-in standby opens at 7am, though the line starts forming around 5:30am. The adjacent USS Missouri, the 1944 Iowa-class battleship where Japan signed the surrender on September 2, 1945, costs $35 and adds about 90 minutes.

Diamond Head, the 300,000-year-old volcanic tuff cone visible from every high-rise balcony in Waikiki, is a 1.6-mile round-trip hike that takes most people 60 to 90 minutes. The trail climbs 560 feet through a series of switchbacks and a narrow 225-foot tunnel built in 1908 for coastal artillery defense. Start before 7am. By 9am the trail feels like a single-file queue, and the exposed rock radiates heat that can reach 35°C by midmorning. Reservations have been required since May 2022, $5 per person through the Hawaii state parks site. The summit overlooks the full sweep of Waikiki Beach to the west, Honolulu Harbor, and the Ko'olau Range to the north. Bring water, wear shoes with actual tread (the concrete steps near the top are smooth and steep), and expect your shirt to be soaked through by the summit. The trade wind at the crater rim dries you off in about 3 minutes.

ʻIolani Palace sits at the corner of King and Richards streets in downtown Honolulu. It dates to 1879 and is the only royal palace on United States soil. That fact alone makes it worth an hour. The building had electric lighting before the White House, installed in 1887. Guided tours run Tuesday through Saturday, $27 for adults, and cover the throne room, the dining room with its dark koa wood table that seats 40, and the upstairs bedroom where Queen Liliʻuokalani was held for 8 months after the 1893 overthrow. The palace grounds are free to walk, and the banyan trees on the mauka side throw enough shade to drop the temperature a few degrees below the surrounding sidewalk. Mind you, the interior is quiet and deliberately solemn. This is not a decorative-arts tour. It is the place where Hawaiian sovereignty ended, and the docents make sure you understand the weight of that.

A note on what to deprioritize. Waikiki Beach itself is fine, but it is a narrow, engineered strip of imported sand backed by 30-story hotels. You will see it anyway because your hotel is likely on Kalakaua Avenue. The Honolulu Zoo, founded in 1910 in Kapiʻolani Park, is small and skippable if your days are limited. Aloha Tower, the tallest structure in Hawaii when it opened in 1926, now sits in a mostly quiet retail complex at Pier 9 and takes 15 minutes from the sidewalk. If you have a third day, spend it at the Honolulu Museum of Art on Beretania Street, founded in 1922. Admission is $20. The central courtyard smells like plumeria year-round, the galleries stay cool and uncrowded on weekday mornings, and the collection of Asian and Pacific art runs to over 55,000 pieces.