Be suitably dressed! And that means a lot more clothes than you imagine unless you are used to very intense sun.
Not even the best sunscreen can keep untrained skin from getting burned if it is exposed to this sun for hours on end.
Get lightweight, long sleeved shirts in a quality that dries fast. Get zipoff trousers of the type meant for warm weather use. Make sure it has a sunscreening effect. Bring shoes or socks to protect from sunburns on your feet and bring a cap with a large bill and preferably a 'skirt' on the back to cover ears and neck.
If you sunburn easily, make sure that you bring some gloves. Yes, gloves! The sun is merciless on the back of your hands, and stripping gloves will not only keep them protected, but also ensure that the salted fly line does not cut into your wet fingers.
The glasses is one of the most important pieces of equipment you have for tropical fishing. Spotting fish under water is essential, and good glasses are utmost important.
Large glasses with good side coverage will exclude all stray light. The lenses should be polarizing and dark amber or brown in color.
Mount them on a cord around your neck for convenience and safety. Glasses flying over board during fast sailing are unlikely to be recovered.
Bonefish like they are found in Belize can be handled with rods between 7 and 9 weight. 9' is the length of choice. Longer rods will probably tire you in the wind.
The lines are floating WF's and make sure to get lines specialized for tropical salt. Lines for more temperate fishing will literally melt and become very limp and even sticky. I used Rio's Bonefish lines and was very pleased.
Most reels with a good brake will work. And you will need the brake! These fish take line like none I have caught before. A bad brake will lead to break offs and bird's nests.
Leaders are your average tapered, knotted or coated leaders, but be prepared to fish them long. We managed best on leaders about two rod lengths and even more.
Tippets should certainly be fluorocarbon, as this lightly sinking and very clear line will disturb the finicky fish as little as possible. 0.30 and 0.28 millimeters will suffice for most situations.
These potential giants require stuff close to the heaviest gear available. 11, 12 and 13 weights are come into play here, and many fishers prefer rods with an extra fight handle. You need lifting power, yet low weight and castability.
The reels are similarly critical. Large reels with plenty backing and a really good brake is a must. 2-300 yards of backing is common and the brake must be guaranteed not to burn down under numerous explosive runs.
Again the floating WF line must be suitable for tropical temperatures, and a second spool with an intermediate line might come in handy. Special tarpon tapers can be desirable for the heavy flies and leaders.
The leaders are a story all to itself. Constructing tarpon leaders is quite a task, and the job should fundamentally be left to someone with experience. As we are potentially talking 50+ kilos (100+ lbs.) and maybe once-in-a-lifetime chances the leader is critical, and its many parts and complex knots can be quite intimidating.
On the reef you chum for fish and all the typical reef fish will gather. Many can be caught on a fly including different jacks.
If you want barracuda or shark different methods have to be applied. Trolling for barracuda. Baiting for sharks.
The need for equipment will vary depending on your quarry, but the potential catches calls for something around and above a 9 wt. and the really big ones can easily give a 12 wt. a more than decent load.
Lines will follow the rod. Floaters will usually do, but sinking lines can be handy too. Make sure you have wire or very heavy mono to make bite tippets, especially for the barracuda. If you want to fish bait you might want to bring some bare hooks in suitable sizes. Stripped down flies can also double as bait hooks.
Bring snorkeling gear too. The chumming will gather a wealth of different fish and you will definitely want to take them in closer eyesight.
Do not cheat yourself of the pleasure of walking and wading along the beach and fish for whatever you see. Gear up for bonefish, which are probable everywhere, but be mentally prepared for everything from shad to barracuda. Use a long leader and light flies as most places are quite shallow.
Wear socks and a pair of old tennis shoes or real flats wading boots if you are so inclined. Do not be tempted to go barefoot or even in sandals. Shells, stones and coral sand will kill you. And if that is not the case the mud will creep in everywhere.
Needless to say that the water is salt, and the hooks need to be stainless.
For bonefish you will need small, mainly tan flies - weighted and not. Crazy Charlie, Gotcha and similar styles will do. A tan Woolly Bugger or a Hare's Ear Nymph will too. Tie the bonefish flies from size 10 to 2 - plenty in the small 6 and 8 range. Make sure to include some with weed guards. A fly snagging the turtle grass will stir the suspicion of most bonefish.
For tarpon you need a selection of standard tarpon flies. Sizes vary from size 2's for smaller fish to 3/0 and larger for the bigger ones. The patterns are numerous, but make sure you have a selection of both colorful ones and more subdued patterns in white, gray and tan. Use needle sharp hooks of the best quality! Do not compromise here.
For barracuda a selection of large, mainly green and blue or gray flies with plenty flash will work fine.
Remember to bring some thin wire for bite tippets and pliers to bend and cut it. The fish' teeth will cut almost any thickness of mono in an instant.
For the odd permit you need some crab patterns in varying sizes.
Other species like jacks, snappers, shad and pompano will take a variation of flies, and most of them are not that critical.
Do not miss the chance for a snorkeling trip under the piers in town and on or behind the reef. Bring a mask, snorkel and fins on your fishing outings too - especially if you go out on the reef side. You will surely see something that will make you want to look closer. A wet suit can be great if you want to dive or snorkel deeper, but most of us will be fine without.
Bring pliers and cutters for thick mono and cutting and bending wire. A set of artery clamps for unhooking fish - especially barracuda - will be practical too. If you are really serious about bigger fish - from jacks to tarpon - a Boca grip might also be neat to have.