Warm Layers:
A puffy jacket or hoody is nice for the plane ride and for when you arrive back home to whatever frigid weather you fled in the first place. This will likely only be used on either end of your trip and stashed away during your stay on the island.
Rain Jacket:
One high-quality, lightweight, breathable, packable rain jacket. Try to choose a color that is not overly bright, as flats fish have notoriously sharp eyesight.
Hats:
Two fishing or baseball hats.
Sun Gloves / Stripping Guards:
Two pairs of sun gloves, along with spandex stripping guards, can save your hands and fingers from both sunburn and line burn.
Lodge Shoes:
One pair of flip-flops or Crocs to wear on the plane and around the lodge.
Face Sun Protection:
At least two Buff-style facial sun protectors.
Sunglasses:
At least two pairs, and possibly more. Fishing without polarized sunglasses is nearly impossible. Plan on a general-purpose lens color such as brown or copper, along with a lighter amber or yellow lens for cloudy or rainy conditions. A backup general-purpose pair can be critical in the event of loss or breakage. The nice thing is that these are likely the same glasses you would wear fishing almost anywhere else, so they will have utility well beyond Christmas Island. Do not forget a few lens-cleaning cloths as well.
Lip Balm:
One tube of SPF 30+ lip balm
Sunscreen:
SPF 50+. We like to have at least one large bottle, along with several smaller containers that can be spread between your boat bag, sling or fanny pack, and even your pockets.
Camera:
Do not forget extra batteries and a waterproof case or bag.
Headlamp:
One small LED headlamp with extra batteries.
Snacks:
Assorted energy bars, nuts, beef jerky, and other snacks to supplement lunch. Electrolyte packets to add to your water are also highly recommended.
Baggies:
A handful of various Ziploc bags can be very handy for keeping snacks and smaller items dry and organized.
Toiletries Kit:
Toothpaste and toothbrush, deodorant, razor, lotion, mini shampoo bottle, Advil, liquid bandage for minor finger cuts, sleep aids, ear plugs, Band-Aids, antibacterial ointment, Benadryl, Gold Bond powder, seasickness medication, and antibiotics prescribed by your doctor.
First Aid Kit:
A small first aid kit for the inevitable cuts, scrapes, and other minor eventualities.
Water Bottle:
One reusable water bottle.