I bring my full dive kit (mask, fins, wetsuit, regulators, bcd, and computer) plus accessories such as SMB, reel, primary dive light, backup dive light, and camera. Save a dive kit includes: spare mask, mask strap, fin straps, regulator mouthpiece, oct keeper, o-rings, mini tool kit, zip ties, duct tape, inner tube patch material, aquaseal, silicone grease, batteries (computers, flashlights, camera strobe, camera), camera memory cards, and seasickness medicine (Bonine). A quick-dry microfiber towel and a jacket are also useful during surface intervals.
Have a great trip!