Organize your daypack so that it can be used not only for hiking and beach use, but also as a “purse” that you can drag with you everywhere, thereby leaving your car free of valuables.
Antibiotic ointment. Little cuts linger in the tropics.
Band Aids (add gauze pads and Ace bandage for extra safety)
Bandana - For sun protection, towel, napkin, fashion accessory, sling
Hydrogen peroxide in small squeeze bottle (optional, to wash cuts)
LED Flashlight or headlamp plus extra batteries. Also a good idea to carry matches or a butane lighter.
Food (energy bar, jerky, nuts). In addition to packed lunch. Good for big and little emergencies.
Ibuprofen (or other pain tablets and other medications you use)
Mosquito repellant (needed more in summer)
Swiss Army knife
Water (drink at least two liters per day)
Water pump, SteriPEN, or treatment tablets (optional). Do not drink stream water in Hawaii.
Whistle. Can be a lifesaver to call for help.
Hiking pole (retractable). Very useful on Hawaii’s steep, slick trails, and for stream crossings and beating down spider webs. Also helpful to probe thick greenery for footing.
Snorkeling gear (mask, snorkel, fins). Snorkeling gear can be purchased cheaply in Hawaii at Costco, Long’s, Wal Mart, etc. Fins that will accommodate your surf shoe are good for rocky entries and the snorkel-hikes (sniking) to offshore islands. Rentals are also available and may be cheaper if you only snorkel a day or two. Also pick up some mask de-fogger, which comes in a little squeeze bottle and works better than spit.
Umbrella (retractable, optional). Easy to pack. Can be a smart choice on shadelss beaches and town rain walks.
Camera. GoPro makes a good waterproof model.
Cell Phone. Coverage is not available everywhere, but almost. A cell phone to call 911 in an emergency makes all the difference. Doubles as a camera.
Shoes. A sturdy flip flop (Teva, Reef) is ideal for beach hiking. Be wary of strap-on sandals since sand gets caught inside and chews up your skin. A low-cut or lightweight cross-training or hiking shoe is good for mountain trails. Don't worry about waterproof shoes, since you will most likely end up slopping through the mud and crosssing streams above the top of the shoe.
Your Trailblazer Travel Book. Essential gear for the trail, beach, river, park, grotto, lagoon, cultural site, off-the-beaten track hotspot.