What should I pack for Koh Tao?

Shoes will matter more on Koh Tao than anything else in your bag. The concrete roads out of Mae Haad climb so steeply that rented 125cc scooters whine in first gear, and the trail to John-Suwan Mountain Viewpoint at the southern tip is loose granite and tree roots, with the landowner collecting a small fee at the start. Cheap flip-flops tend to snap on that climb within the first ten minutes. Pack one pair of strap-on sports sandals with a lugged sole, such as Tevas or Chacos; the same pair handles the boulder scramble down to Freedom Beach and the sharp rocks at the waterline of Ao Tanote. Leave white canvas sneakers at home: the red dust on the Tanote road stains them in a day, and by day three in a Sairee bungalow they will smell of wet mildew too.

Most first-timers come to Koh Tao to dive, and the dive shops along Sairee Beach rent every piece of gear, but bring your own mask if you wear glasses or have a narrow face. A rental mask that leaks at 18 metres on a Chumphon Pinnacle trip can ruin a dive that costs well over 1,000 baht. Pack a long-sleeved rash guard as well: it blocks the midday glare on the boat deck and the sting of the small jellyfish that drift into Ao Leuk and Tanote in the wet months. Sunscreen is the one thing to buy at home. The 7-Eleven shops in Sairee charge roughly 450 to 600 baht for a small bottle of Banana Boat, and reef-safe brands are harder still to find. Check that your travel insurance covers scuba to 30 metres and motorbike riding with a valid licence: the scraped knees locals call the 'Koh Tao tattoo' show up at island clinics every week, and serious injuries go by boat to hospitals on Koh Samui.

October is the start of the wet season on the Gulf of Thailand side, which on Koh Tao runs through to December, with November the stormiest month. The showers arrive warm and heavy, drumming on tin roofs for an hour before they clear. A packable rain jacket is worth the space, though a 7-Eleven poncho does the same job. The bigger risk this time of year is the sea. The Lomprayah catamaran from Chumphon takes about 1 hour 45 minutes, and on a choppy crossing the cabin fills with the smell of diesel and other people's breakfast, so take a motion-sickness tablet 30 minutes before you board and wear a light long-sleeve because Lomprayah runs the cabin air conditioning cold. A dry bag keeps your passport and phone safe on the longtail boats to Ao Hin Wong and Mango Bay, where spray comes over the bow.

Carry more cash than you think you need, in a zipped pocket. Thai ATMs charge foreign cards 220 baht per withdrawal, about 6.50 USD at the current rate, so take out the maximum each time at the machines near Mae Haad pier. A headlamp matters after dark: long stretches of road between Sairee and Chalok Baan Kao have no streetlights, and the island grid cuts out during storms. A universal adapter covers the Thai sockets, which take Type A, B and C plugs at 220V. In Mae Haad and Sairee Village, put a shirt on when you leave the sand. Shop signs in both villages ask visitors to cover up away from the beach.