What's a good 3-day itinerary for Honolulu?

Day 1 stays within Waikīkī and Diamond Head, roughly 8 km on foot. Hit the Diamond Head trailhead by 6:30 AM, before the tour buses arrive around 9 and while the trade winds keep the trail below 25°C. The 1.3-km climb gains 170 metres. From the summit you can see Koko Head to the east and downtown to the west. Back down by 8:30, grab breakfast at Bogart's Cafe on Monsarrat Avenue, where the açaí bowl runs about $14. Walk Kalākaua Avenue to Kūhiō Beach by 10:30 and swim in the walled lagoon near the Duke Kahanamoku statue. Lunch at Marukame Udon on Kūhiō Avenue by noon. The line moves fast, about 10 minutes, and a hot udon bowl costs $5-8. You can smell the dashi broth from the sidewalk. Afternoon at Honolulu Zoo in Kapiʻolani Park, founded in 1910, $19 adult entry. Finish at the Moana Surfrider's Banyan Court for an $18 mai tai under the old banyan canopy at sunset.

Day 2 heads 6 km northwest to downtown Honolulu and Chinatown. Start at ʻIolani Palace by 9 AM, the only royal palace on U.S. soil, built in 1879. The guided tour runs 60 minutes and costs $27. Walk 10 minutes to the Honolulu Museum of Art, founded in 1922, where the $20 ticket covers 50,000 works across 30 galleries. The central courtyard smells like plumeria year-round. By 12:30, cross into Chinatown on North Hotel Street for lunch at Livestock Tavern, or grab pig's feet soup at Maunakea Marketplace for $8. The market stalls sell leis for $5-15. The tuberose ones have the strongest scent. Afternoon at the Cathedral Basilica of Our Lady of Peace on Fort Street, built in 1843, the oldest Catholic cathedral in continuous use in the U.S. Walk to Aloha Tower, built in 1926, for a free observation-deck view of the harbour. Dinner at Pig and the Lady on North King Street, where the pho French dip runs about $19.

Day 3 requires a 20-km drive west to Pearl Harbor. Book USS Arizona Memorial tickets at recreation.gov at least two weeks ahead. They release at 7 AM HST and sell out the same day. Arrive at the Pearl Harbor Visitor Center by 7 AM for the 7:45 documentary screening. The memorial sits above the sunken hull of the USS Arizona, sunk on December 7, 1941, with 1,177 crew still aboard. Oil still rises from the wreck. Small black drops that break into rainbow sheen on the water surface. Free entry. From the memorial, walk to the USS Missouri, the 1944 Iowa-class battleship where Japan signed the surrender document in Tokyo Bay on September 2, 1945. Admission runs $35. Allow 90 minutes. The USS Bowfin submarine is next door, $15 entry. You'll feel the cramped steel bunks and catch the diesel smell that still clings to the engine room. Back in Waikīkī by 3 PM for a swim at Sans Souci Beach, a quieter strip east of the War Memorial Natatorium where the sand is coarser and the crowds thin out.

Total walking and transit distance across three days comes to about 55 km, with the Pearl Harbor drive making up most of Day 3. Mornings tend to run around 23-24°C with 75% humidity, rising to 30°C by midday. Wear reef-safe sunscreen. Hawaiʻi state law has banned oxybenzone and octinoxate formulas since January 2021. TheBus costs $3 per ride or $7.50 for a day pass and covers all three days' routes. A rental car helps on Day 3 but is dead weight on Days 1 and 2, where Waikīkī garage parking runs $25-40 per day.