Most tourists entering Thailand for fewer than 30 days do not require a visa.
If you are visiting Thailand as a tourist you are likely to be eligible to enter the country under the ‘Visa Exemption‘ rule as long as your passport is valid for at least 6 months beyond the date of your entering the country.
This rule states that passport holders from 52 countries are allowed to enter Thailand as long as they are entering for tourism purposes and have a confirmed return ticket to show that they are flying out of Thailand within 30 days.
Among the 52 eligible countries are Australia, Canada, France, Germany, Hong Kong, Italy, Japan, New Zealand, Russia, Singapore, United Kingdom and United States.
The Thai Embassy is responsible for setting and enforcing the rules for entry into Thailand. If you are unclear about any aspect of the entry requirements you should contact your local Thai embassy before you travel.