How to Pack for a Tropical Trip

Focus on lightweight, moisture-wicking synthetic fabrics and limit yourself to one carry-on bag to stay mobile. You only need two swimsuits, three pairs of shorts, and five shirts, regardless of how long you are staying.

Select a lightweight bag. Use a 30L-40L backpack rather than a hardshell suitcase. You will be moving over sand and uneven pavement; wheels are a liability in tropical climates.
Prioritize fabric over quantity. Pack linen, merino wool, or synthetic 'dry-fit' shirts. Avoid heavy cotton or denim, as they hold moisture, stay damp in humidity, and take days to air dry.
Use packing cubes for compression. Group items by category. Use one cube for beach gear, one for tops, and one for bottoms. This keeps your clothes organized when you inevitably encounter high humidity or sand in your bag.
Minimize footwear. Take exactly three pairs: one pair of sturdy waterproof sandals (for beaches and showers), one pair of lightweight breathable sneakers (for travel days and hiking), and one pair of flip-flops.

Should I bring a hoodie?: Yes. Bring one lightweight zip-up or pullover. Air-conditioning on planes and in some transit hubs is set to freezing temperatures, even if it is 95 degrees outside.
How do I deal with wet laundry?: Bring a dedicated waterproof 'wet bag' or a heavy-duty ziplock bag to isolate wet swimwear from your clean clothes until you find a place to hang dry.
How many outfits do I really need?: Plan for 7 days of clothing, regardless of trip length. Pack enough detergent to hand-wash items in a sink, and you can rotate your wardrobe indefinitely.