All great suggestions, and the leader information is excellent. I'd like to add that for inshore fishing, you can get away with a level leader, 10-20 lb test, about 8-10' will do. Fish, especially over coral, are generally not leader shy and are actually attracted by line slap or the heavy plop of the fly (the very occasional bonefish might beg to differ). Commercial saltwater tapered leaders work great, tapered to not less than 10 lb, I wouldn't go lighter. Tippet can be 10-20 lb, depending on leader (if tapered). Coral and sand are highly abrasive and SW fishes, even small ones, tend to be toothy. One consideration. Things might have changed since I last fished there in 1999, but be prepared for an audience when you fly-fish from shore. If you can get access to Andersen AFB, your fishing possibilities improve considerably. Offshore leaders, heavy! Very heavy! Wire! Out of curiosity, what reels are you bringing, and how much backing? For inshore Guam, a decent 8 wt reel, think Orvis Hydros, with about 150-200 yds of backing, will do. This is not the Kiribati, so no fears of getting into 20lb trevally or the likes. Offshore, hmm. Even a small Wahoo of about 15 lbs is a handful on a 10 wt (you really want a 12 wt), and a good and reliable drag on your reel becomes paramount. Loads of backing, more than 200 yds. One other thing. Be prepared to lose your catch to sharks (inshore/offshore) and/or dolphins (offshore). Yes, Flipper is an expert fish robber. FWIW, here is a sample of what I would typically bring for my yearly SWFF trip in the Pacific: Nothing fancy, all tried and tested patterns/colors that work for me (you can't see them, but the poppers have eyes, seems to make a difference). You'll need loads of flies, the ratio of flies used to fish caught, in my experience, is above 3 to 1, in the case of poppers maybe above 4 to 1, they get hammered really hard and the fish who go for them are all super-fangy, or maybe I'm just lousy at the SWFF game . Again, out of curiosity, how many days will you be in Guam? Are you flying out on the island-hopper from San Francisco or Honolulu? If you are, you might want to think about stopping off along the way, some of the islands on the route (like Majuro, Pohnpei and Kosrae) offer fantastic inshore/offshore fishing. Kenneth PS. Talking about leaders, Supreme Leader Kim seems real interested in Guam these days, keep an eye out for him. Or his Hwasong toy .