What do you need to rent a scooter in Thailand, legally rather than practically?

A shop being willing to rent to you is not the same as it being legal. Australian government advice is that you need a valid motorcycle licence, warns that some rental companies will tell you otherwise, and states that riding without the correct licence can lead to arrest. The UK FCDO adds that riding without the licence you would need at home can void your travel insurance completely, and that rental scooters in tourist areas are often unregistered and cannot legally be used on a public road. The sourced version is here: https://meetlocale.com/guides/is-thailand-safe-to-travel-alone One separate rule: do not leave a passport as the deposit. https://meetlocale.com/guides/thailand-scams What did the shop you used actually ask you for?