Here's my "Bare Necessities" list for C.I....I've spent a total of 182 days over 11 years on the Kiritimati flats, so this might be worth reading..
The bare necessities....Note that your U.S.luggage allowance may be more generous than 23kg.from Australia,but that's no reason to take more **** than you need.
Start with a bag that doesn't weigh a ton obviously,and everything listed immediately below goes in your big bag in the hold of the aircraft and will come in under 20kg....this includes ALL your fishing equipment! If you're coming to C.I. via Hawaii you MAY be able to take fly fishing gear on board,but IMHO don't risk it..
CLOTHING etc.apart from what you wear on the plane( Crocs or Flips are good as then you can wear them on the island)
2x L/S fishing shirts
2xfishing pants
Buffs/flats gloves
2xhats (peak front is best)
Undies/hankies/T-shirts/light shorts that double as sleep shorts
Light spray jacket or $2 poncho
Towel/soap is provided so I don't take them,but suit yourself.
Wetpack for toiletries (razor,foam etc.) plus Betadine/Savlon for cuts etc.and BBB cream for fork/bum heat rash/Panadol/Ibuprofen(muscular pain) Eye drops!..good quality non-greasy Sunscreen 30+or better,Blistex for your lips,Waterproof Bandaids,dental floss, can reduce some of this medical list if you share with a mate.I've also been taking a tube of Bactroban (prescription only) for nicks/cuts that don't show signs of healing after a day or two,and a small plastic travel size squirt bottle filled with Windex to take out in your boat bag each day to clean your glasses.HINT...go over your feet each evening for nicks and cuts that can quickly get infected in the tropics if ignored.
Flies in boxes/nippers/hook file/Hemostat pliers/tippet & leader spools/spare fly lines/Rio Agent X line cleaner and microfibre cloths.Fly reels, and your rods.I use a 31"PVC tube with end caps (one end sealed) that holds up to 4x4pc.9' rods in their socks top to tail,and a second tube for my GT rod,plus Reel grease/knife and/or Leatherman.etc.I usually take five rods and five reels (2x7wt.1x8wt.1x9wt.1x12wt.) but that's your call of course.
STUFF THAT GOES IN YOUR CARRY-ON CABIN BAG...(I use a waterproof Medium Shimano Boatbag which then doubles up as my fishing bag that goes out with me on the boat each day ) Simms Flats Sneakers with 2x wading socks inside (note spare pair) and a large ziplock bag to put your boots in when you leave C.I. as they'll be wet!!
Camera/charger/spare SD card/lens cleaning tissues,microfibre cloths(line cleaning)..Passport,Travel itinerary etc.(copy of this in your big bag is a good idea)
2xSunglasses/regular glasses if you wear them(cheap"spare pairs" for the flats are fine)
Health/Candy bars/dried fruit etc.
..and anything else that isn't sharp really,even from the Clothing list above.Note the shirt I wear on the plane can double up as a flats fishing shirt,and wearing a pair of your lightweight flats pants on the plane is a good idea too.Hope this helps..