Thailand on a US Licence — Drive on the Left, IDP Required, 0.05 Limit

Two facts decide how an American’s drive in Thailand goes, and both come as a surprise. The first is the side of the road: Thailand drives on the left, the mirror image of home, and rental paperwork almost never warns you. The second is the licence: your US licence on its own is not valid here. You need an International Driving Permit, and it is mandatory rather than a nicety.

Sort the IDP before you fly — AAA issues one in about ten days for a small fee, and you cannot obtain it once you have landed. Police checkpoints do ask for it, and rental firms increasingly won’t release a car without one. Carry it clipped to your US licence and passport.

The left-side switch is the real driving challenge, and it is sharpest on day one — pulling out of a 7-Eleven car park onto the wrong lane, or glancing the wrong way at a junction. Take your first hour somewhere quiet, not in Bangkok or on a Phuket main road. Then there is the texture of Thai traffic: scooters and motorcycles flow up both sides of you, weave through gaps and treat lane markings as decoration. Leave space, signal early, and never assume a rider has seen you.

On alcohol, Thailand is stricter than the US — 0.05 against 0.08 — and checkpoints, especially at night near tourist areas, are routine. With so many two-wheelers around, treat it as zero. Speeds run higher than you might expect, up to 120 km/h on the tolled motorways, and a serious overshoot of 20 km/h or more can bring a fine in the THB 1,000-2,000 band; a smaller one is THB 500-1,000. You can model a penalty with the Speeding Fine Calculator, and our Thailand driving guide has the route detail. If a fine follows you home, who pays driving fines abroad explains how it works. Police emergency is 191.