What to pack for Koh Samui in May
Heading to Koh Samui in May? Here's a packing list built directly from local climate averages — not generic blog advice.
May is one of the hottest months of the year in Koh Samui (ranked 2 of 12) and among the rainiest (ranked 2 of 12). Day temperatures are flat compared to April and holding steady into June — so this month's packing list won't be identical to April's or June's.
Essentials
- ★ Passport + a photocopy stored separately Travel documents
- ★ Phone + charging cables (USB-C, Lightning as needed) Daily essentials
- • Refillable water bottle (1L) Reduces single-use plastic + saves money
- • Compact daypack (15–20L) For day trips, hands-free walking
- • Travel-size first-aid kit (band-aids, ibuprofen, antihistamines) Pharmacy access varies
Tops
- ★ Lightweight LINEN shirts (3) — short and long sleeve Avg high 30.5°C, humid — linen wicks sweat, breathes, dries fast
- ★ Breathable t-shirts (4–5) — linen-blend, bamboo, or merino Avoid pure cotton in this heat
- · Tank tops (2) Peak heat hours
Bottoms
- ★ Lightweight breathable shorts (3–4) — linen or quick-dry Avg high 30.5°C
- • 1 pair of light long pants Sun cover for long days + AC indoors
Outerwear & layers
- · Light cover-up (linen overshirt or scarf) for AC indoors Malls, restaurants, transport are arctic
Rain & weather protection
- ★ Full waterproof shell jacket (Gore-Tex or similar — NOT a 'water resistant' soft shell) 29 rain days, 130 mm
- ★ Compact umbrella (windproof, vented) Heavy rain — basic umbrellas invert in wind
- ★ Quick-dry pants (1 pair) Cotton/jeans become miserable when soaked
- • Waterproof phone pouch + dry-bags for electronics Heavy rain WILL find its way in
Footwear
- ★ Walking sandals with arch support (Teva, Chaco, Birkenstock) Warm weather comfort
- ★ Comfortable closed-toe walking shoes — sneakers Long sightseeing days, religious sites, traffic-dodging
- • Flip-flops or pool slides Koh Samui is a beach destination
Accessories
- ★ Insect repellent (DEET 25%+ or picaridin) Mosquitoes thrive in warm + wet weather
- • Sunglasses Bright days expected
- • Sunscreen (SPF 30) Year-round basics
Power, voltage & adapters
- ★ 220V at 50Hz Mains electricity standard for Thailand
- ★ Plug types: O, A, B, C (Type O — flat/round 3-pin (Thailand)) Most common: O. Older buildings may also use A, B, C.
- ★ Check device voltage labels: 'INPUT: 100–240V' is dual-voltage (most modern phones, laptops, chargers — safe). Single-voltage 110V devices (older hairdryers, curling irons) need a step-down converter, not just an adapter. Thailand runs 220V — too high for US-only 110V devices
- • From the UK/Ireland: bring a G→O travel adapter UK Type G plugs don't fit Thailand's outlets
- · Easiest option: a universal travel adapter (e.g. Anker, Epicka) that handles A/B/C/E/F/G/I in one — covers ~95% of countries. If you travel to multiple regions
✅ Can you carry-on?
Yes — May in Koh Samui packs comfortably into a carry-on. Conditions stay mild enough that you can rely on light layers, one pair of shoes, and a packable rain shell.
26 suggested items total — 5 essentials, 6 clothing items, 3 pairs of shoes.
What you can leave at home
Based on Koh Samui's May climate, here's what won't earn its bag space:
- heavy winter coat & thermal underwear
- gloves, scarves, and wool hats
- delicate suede or leather shoes (they'll get ruined)
- snow boots and ice grips
How this list was built
Every recommendation above maps to specific climate data for Koh Samui in May: average high (30.5°C), average low (26.6°C), expected rain days (29), and any peak hazard seasons. Heavier items appear at colder temperatures; rain gear scales with how often it rains; sun protection appears when it's warm and dry.
The ★ items are essential — pack these first. The • items are recommended for comfort. The · items are nice-to-have if you have space.
Other months in Koh Samui
Daily forecasts, climate averages, and the best activities for the season.