Probably the most important thing to tuck into your suitcase is sunscreen. There are many tanning oils on the market in Hawaii, including coconut and kukui (the nut from a local tree) oils, but they can cause severe burns. Hats and sunglasses offer important sun protection, too.
Hawaii is casual: sandals, bathing suits, and comfortable, informal cotton clothing are the norm. In summer, synthetic slacks and shirts, although easy to care for, can be uncomfortably warm. The aloha shirt is accepted dress in Hawaii for business and most social occasions.
Shorts are acceptable daytime attire, along with a T-shirt or polo shirt. There’s no need to buy expensive sandals on the mainland—here you can get flip-flops for a couple of bucks and off-brand sandals for $20 or less. Many golf courses have dress codes requiring a collared shirt. If you’re visiting in winter or planning to visit a high-altitude area, bring a sweater, a light- to medium-weight jacket, or a fleece pullover.
If your vacation plans include an exploration of Maui’s northeastern coast, including Hana and Upcountry Maui, pack a light rain jacket. And if you’ll be exploring Haleakala National Park, make sure you pack appropriately, as weather at the summit can be very cold and windy. Bring good boots for hiking at Haleakala Crater; sneakers will suffice for most other trails on Maui.