Driving & transport law
Licences, IDPs, helmets, alcohol limits, and what happens after an accident.
What licence you need: foreign licences, IDPs and the two conventions
Thailand recognises foreign licences through treaties, not by default. Under section 42 bis of the Vehicle Act B.E. 2522 (1979), a foreigner admitted to Thailand temporarily under immigration law may drive on a licence issued by a country that has a recognition agreement or convention with Thailand, only for the vehicle categories written on that licence, and must carry it together with the documents the treaty requires. In practice that means your home licence plus an International Driving Permit, or a home licence recognised directly by agreement (ASEAN member-state licences work this way). Thailand is party to both road-traffic conventions: the 1949 Geneva Convention and, since 1 May 2021, the 1968 Vienna Convention, so IDPs issued under either are valid here. The Department of Land Transport is explicit that an IDP is used together with, never instead of, the domestic licence behind it — an IDP alone is not a licence. The folklore correction most riders need: the licence must match the vehicle. A car licence with a car-only IDP does not cover a motorcycle. Riding outside your licensed category is treated as driving without a licence — Vehicle Act section 64, up to one month imprisonment or a fine of up to 1,000 baht, or both. There is no fixed day-limit in the Act itself: a tourist may drive for as long as they are lawfully in the country on a temporary stay and both documents remain valid (Geneva-convention IDPs run one year from issue; Vienna-convention IDPs up to three). Anyone settling in should convert to a Thai licence.
Getting a Thai driving licence: documents, medical certificate, tests
A first Thai licence is a temporary one issued under the Vehicle Act B.E. 2522 (1979); section 44 makes it valid two years, after which you move to the five-year personal licence. Minimum age is 18 for cars and motorcycles, or 15 for a motorcycle up to 110cc. Cars and motorcycles are separate licences — you apply for each. The Department of Land Transport's own checklist for foreigners: passport (with copy) or alien identification, plus proof of where you live — either a certificate of residence issued by Immigration or your embassy, or a still-valid work permit showing your address — and a medical certificate in the Medical Council format stating you have no condition dangerous for driving, issued no more than one month before applying. Queues must be booked ahead via the DLT Smart Queue app or gecc.dlt.go.th. The process at the office: document check, physical aptitude tests (colour vision, depth perception, peripheral vision, brake-reaction), at least five hours of training, the electronic written exam, then the practical driving test on the DLT course; fee payment closes at 15:30. The common forum error is treating the residence paperwork as optional: without the immigration residence certificate, an embassy letter or a work permit bearing your address, the application does not start. If you hold a valid foreign licence of the same class, DLT offices commonly reduce or waive the training and written exam — exact practice varies by office — but the physical aptitude tests and the document checklist still apply.
Helmet law: riders AND passengers, and how it is now enforced
Section 122 of the Road Traffic Act B.E. 2522 (1979) requires both the motorcycle driver and the passenger to wear a crash helmet, and separately forbids the driver from riding while a passenger is unhelmeted — the driver commits their own offence for an unhelmeted pillion. The only statutory exemptions are monks, novices, priests and followers of faiths wearing traditional head coverings, plus anyone exempted by ministerial regulation. Helmet standards and manner of wearing are set by ministerial regulation, so an unfastened or novelty helmet does not comply. The penalty was raised by the Road Traffic Act (No. 13) B.E. 2565 (2022), in force 5 September 2022: riding or travelling without a helmet now carries a fine of up to 2,000 baht (it was 500 baht for decades, which is why old forum threads quote tiny figures). A helmet offence also deducts one point under the driving demerit system that started 9 January 2023. On enforcement: the long-standing street reality of warnings and token fines has been deliberately ended. After a grace period of formal warnings, the Royal Thai Police moved to strict "catch and actually fine" enforcement of ten priority offences — helmets for driver and passenger among them — nationwide from 1 April 2026. Passengers are fined in their own right; the common belief that only the driver is liable is wrong.
Drink-driving: the 50mg and 20mg limits, refusal, and the real penalties
Driving while drunk is prohibited by section 43(2) of the Road Traffic Act B.E. 2522 (1979). The limits sit in Ministerial Regulation No. 21 (B.E. 2560, 2017): over 50 milligram-percent blood alcohol counts as drunk for ordinary licence holders, but the threshold drops to just 20 milligram-percent — roughly one drink — for drivers under 20 years old, holders of a temporary (first two-year) licence, and anyone driving with no licence or a suspended or revoked one. New arrivals on a fresh Thai licence are in the 20mg group and rarely know it. Officers with reasonable grounds may order a test (s. 142); refusing without reasonable justification means you are legally presumed drunk, and you can be detained until testing is completed. Penalties under section 160 ter: up to one year imprisonment or a 5,000–20,000-baht fine or both, plus licence suspension of at least six months. The 2022 amendment (Road Traffic Act No. 13, in force 5 September 2022) added a repeat-offender rule: a second offence within two years carries up to two years imprisonment AND a 50,000–100,000-baht fine — the court must impose both — with at least one year's suspension. Causing injury raises it to 1–5 years; serious injury 2–6 years; death 3–10 years with a 60,000–200,000-baht fine and permanent revocation. A drunk-driving offence also deducts four demerit points, and the standard voluntary motor policy excludes your own-damage cover above these same limits.
Police stops and traffic tickets: what officers may do and how to pay properly
Sections 140–142 of the Road Traffic Act B.E. 2522 (1979) govern the stop-and-ticket process. An officer who sees (or captures on camera) a violation may warn you or issue a traffic ticket stating the fine; for camera tickets the notice is posted to the vehicle owner, who is presumed liable unless they prove someone else was driving. Officers may order you to stop and, with reasonable grounds, test you for drink or unfitness. Serious offences (drunk, reckless, hit-and-run) cannot be settled with an on-the-spot ticket fine at all — they go to the investigation officer and usually a court. Section 141 gives lawful payment routes: at the place stated on the ticket (police station), by post, and today through the channels on the ticket's barcode — Krungthai Bank and its NEXT app, post offices, CenPay counters, or the Royal Thai Police e-ticket portal (ptm.police.go.th), where you can also look up outstanding tickets. Every lawful payment produces a receipt; cash pressed into a hand at the roadside does not. Ignore a ticket and section 141 bis lets police summons you and have the registrar hold up your annual vehicle-tax renewal until it is resolved. Since 9 January 2023 a demerit system runs alongside fines: every licence holder has 12 points; offences deduct 1–4 (helmet or speeding 1, red light 2, hit-and-run 3, drunk driving 4). At zero points the licence is suspended 90 days — driving anyway risks three months' jail or 10,000 baht. Points return after a year, or through a DLT retraining course.
Accidents: your duties at the scene and what Por Ror Bor actually pays
After any accident causing damage to people or property, section 78 of the Road Traffic Act B.E. 2522 (1979) requires the driver — at fault or not — to stop, give appropriate assistance, report to the nearest competent official without delay, and give name, address and registration number to the injured party. Leaving the scene creates a legal presumption of guilt and lets police seize the vehicle; the basic penalty is up to three months or 2,000–10,000 baht, rising to six months and 5,000–20,000 baht where someone was seriously hurt or killed (s. 160). Every registered vehicle, motorcycles included, must carry compulsory accident-victim insurance (Por Ror Bor) under the Protection for Motor Vehicle Accident Victims Act B.E. 2535 (1992), s. 7. The owner who fails to insure and anyone who uses an uninsured vehicle each face fines up to 10,000 baht (ss. 37, 39), and annual vehicle tax cannot be renewed without it. What it pays: initial damages within seven days, no fault proof needed — actual medical costs up to 30,000 baht per person, and 35,000 baht for death or loss of organ (combined cap 65,000). Once the other driver's fault is established, cover rises to 80,000 baht medical, 200,000–500,000 for loss of organs or permanent disability, 500,000 for death, plus a 200-baht daily inpatient allowance for up to 20 days. Two catches the forums miss: the at-fault driver personally receives only the initial damages, and Por Ror Bor covers people only — never vehicle or property damage. Victims of uninsured or hit-and-run vehicles claim the same initial damages from the state Victims Compensation Fund; the claims hotline is 1791.
Renting cars and bikes: licence classes, big bikes, and the insurance trap
A rental shop handing you keys does not make you legal. To ride any rented motorcycle you need a motorcycle-category licence — a Thai one, or a home-country motorcycle licence recognised under section 42 bis of the Vehicle Act B.E. 2522 (1979) (usually via an IDP). A car licence covers cars only; riding on it is driving without a licence (s. 64: up to one month or 1,000 baht). For "big bikes" — motorcycles of 400cc or 35kW and up — Department of Land Transport rules under the Ministerial Regulation on driving-licence issuance B.E. 2563 (2020) additionally require certification from a DLT-approved training provider on top of the ordinary motorcycle licence. What shops rarely explain is the insurance position. Only Por Ror Bor accident-victim cover is compulsory, and it pays injured people, not the bike or car. Whether the vehicle itself is covered depends on a voluntary policy the shop may or may not hold — and the OIC's standard motor policy (Registrar's Order 46/2567) excludes own-damage cover when the vehicle was driven by someone who has never held any driving licence, has been disqualified, or is using a motorcycle licence to drive a car; a separate exclusion voids it for alcohol over the 50mg/20mg limits. So an unlicensed or wrong-licensed renter typically pays for the crashed vehicle out of pocket, on top of fines and their own hospital bills — Por Ror Bor gives an at-fault driver only the initial damages tier. Check the actual policy, not the shop's verbal assurance, before signing.
General information, not legal advice. Laws and practice change; for a decision that matters, confirm with the authority named in the sources or a licensed professional.