The length of time that you can stay in Thailand without a visa depends on your nationality and the purpose of your visit. For most countries, tourists are allowed to stay in Thailand for up to 30 days without a visa, as long as they have a valid passport and an onward or return ticket.

However, if you wish to stay in Thailand for longer than 30 days, you will need to apply for a visa before you travel. There are several types of visas available, including tourist visas, business visas, and student visas, which allow you to stay in Thailand for different lengths of time.
It’s important to note that overstaying your visa in Thailand can result in fines and other penalties, so it’s important to make sure you have the appropriate visa for your intended stay. If you are unsure about the requirements for your visit, it’s a good idea to contact the Thai embassy or consulate in your home country for more information.