Downtown Honolulu
One of the finest art museums in the Pacific — uncrowded, high-quality, and beautifully laid out around several garden courtyards. The Japanese art collection is exceptional (one of the best in the US outside major mainland cities). European works include Monet, Matisse, Gauguin, Rodin. The permanent Hawaiian art gallery upstairs is thoughtfully curated. The courtyard café is a lovely lunch stop. Allow 2 hours but could easily fill half a day.
Tickets at honolulumuseum.org or at the door. $25 adults / free under 18. Open Tue–Sun 10am–4:30pm. Closed Mondays. Located at 900 S Beretania St.
Fully indoor — good rainy day option. Courtyard restaurant requires a reservation for lunch.