Cannabis and Driving in Thailand: Where the Law Is

There is no legal cannabis limit for drivers in Thailand, because there is no measured threshold at all. No THC figure has been published, and there is no cannabis-specific driving offence. Driving while impaired by cannabis falls under the general prohibition in section 43(2) of the Land Traffic Act — driving "while got drunk of alcohol or other intoxicant" — and whether you were impaired is decided by the officer who stops you and, after that, by a court.

That is a worse position for a driver than a numeric limit, not a better one. With alcohol you can at least know what the line is. With cannabis there is nothing to be under, no reading that clears you, and no way to argue that a small amount some hours ago put you on the right side of a figure that does not exist.

• Published THC limitNone
• Which law appliess.43(2) intoxicant rule, and s.43 bis for scheduled substances
• How impairment is judgedBy the officer, then by the court
• Refusing a drug examinationDetention until it is done, plus a fine of up to 1,000 baht

Two separate provisions, and cannabis can meet either

Thai traffic law approaches drugs from two directions.

Section 43(2) is the general intoxication rule. It is the same provision that catches alcohol, and its wording is broad: alcohol "or other intoxicant". It contains no numbers for anything, and for cannabis there is nothing to measure against in any event.

Section 43 bis prohibits a driver from consuming narcotics or psychotropic substances as prescribed by the Commissioner-General of the Royal Thai Police by publication in the Government Gazette. It is a list-based provision: what is on the list is set administratively rather than in the Act. Officers, inquiry officials and Inspectors may examine drivers of prescribed categories of vehicle, and where a preliminary test is negative the driver may continue on their way.

We are not going to tell you where retail cannabis law currently stands

The legal status of buying and possessing cannabis in Thailand has changed several times in a short period, and it is not this site's subject. Every source we could find that describes the current position is a dispensary or a cannabis-industry page, which is not a standard we would rely on for anything with legal consequences.

What we will say is that the retail question and the driving question are entirely separate, and that assuming the first answers the second is the mistake to avoid. Cannabis being sold openly on a high street tells you nothing about driving afterwards. Alcohol is sold openly everywhere in Thailand too, and driving on it will put you in front of a court.

What happens at a roadside stop

Drug testing at a Thai checkpoint is far less routine than breath testing, but the power exists and it is used, particularly where an officer forms a view that a driver is impaired and the breath test comes back clear. That combination — obviously not right, no alcohol — is exactly the situation section 43 bis is written for.

If you refuse the examination, two things happen, and they are different from what happens when you refuse a breath test:

So refusing a drug examination is the lesser offence of the two — and still pointless, because you are held until it happens. Many sources blur these two situations together; they are not the same, and the difference is set out properly in refusing a breath test in Thailand.

What a positive result leads to

Section 157/1 sets the penalty for driving after consuming narcotics or psychotropic substances in an unusual way: one third more than the penalty that applies under the narcotics or psychotropic substances law for the substance concerned, plus suspension of the driving licence for at least six months or revocation of it. Where the driving causes injury, serious injury or death, the escalations mirror the drink-driving bands — 1 to 5 years and 20,000 to 100,000 baht for injury, 2 to 6 years and 40,000 to 120,000 baht for serious injury, and 3 to 10 years and 60,000 to 200,000 baht plus revocation where someone is killed. For scale, 100,000 baht is roughly £2,250, $3,000 or €2,600.

Where a case is brought under section 43(2) as ordinary intoxication rather than under the scheduled-substance route, the penalty structure is the drink-driving one described in drink-driving penalties in Thailand. Which route a particular case takes is not something we can predict from the outside. Both end in a court file rather than a ticket — section 140 excludes the drug-driving and drink-driving offences from the fixed-penalty process, so neither can be settled at the roadside.

For anyone holding a Thai licence, driving under the influence of illicit drugs also sits in the top band of the licence points system, at four points from a starting balance of twelve.

Where the law may be heading

As of 2022 the Department of Land Transport was publicly pushing for an explicit cannabis ban for drivers, starting with public-transport drivers. We could not find a completed instrument, and we are not going to describe a rule that may not have been made. If a specific cannabis provision is enacted, it will most likely arrive as a Gazette announcement under section 43 bis rather than as a change to the Act itself — which is to say quietly, and without much English coverage.

The practical position

Riding a scooter in Thailand already asks a lot of a visitor: unfamiliar machine, left-hand traffic, dense two-wheeler flow, and a road system that runs on reading other people's intentions rather than on signalled priority. That last part is what cannabis interferes with most — judgement of speed and distance, and the constant low-level negotiation with other road users described in right of way in Thailand. There is no threshold to be under, so the only position that is legally clear is not driving.

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