Can I rent a scooter with the licence I already have?

Short answer

Not on its own. Thailand recognises an International Driving Permit issued under the 1949 Geneva Convention, or a licence from another ASEAN country, and you carry it together with your passport and your home licence. A shop handing over the keys is not the body that decides this.

What Thailand recognises

Two documents: an International Driving Permit issued under the 1949 Geneva Convention on Road Traffic, or a driving licence issued by another ASEAN member country. A licence from home, by itself, is neither of them.

The Royal Thai Embassy frames it as a legal requirement rather than advice, and is specific about what you carry: the international permit, your passport and your national licence, produced together when an officer asks.

The rental counter is not the authority

Shops rent scooters to people who cannot produce any of this. That is a fact about shops, not about the law. The check that counts happens at a roadside stop, once the bike is already yours for the week.

Which is why "but they rented it to me" carries no weight in the conversation that follows. The counter was never the body deciding whether you were permitted to ride.

If your licence does not qualify

Go to the Provincial Land Transport Office in the province where you entered the country.
Take the physical fitness test.
Sit the one-hour training session.
Pay the fees — 205 baht for the licence, plus 100 baht for the photograph and plastic printing.
Collect a temporary driving licence, valid for 30 days.

Bring a passport with at least six months of validity, a certificate of address from your tour operator, a medical certificate issued within the past month by a licensed physician, and your foreign licence for the same vehicle category with an authorised Thai translation.