Visa Exemption Rule
This rule allows tourists from 55 countries (U.S., Canada and UK included) to enter Thailand without a visa. They are granted to stay a maximum of 30 days if they are entering Thailand via an international airport or through a land border checkpoint.

Under the new provisions of the Visa Exemption Rule and Bilateral Agreement, effective December 31, 2016, passport holders of these 55 countries are entitled to enter Thailand under this rule provided they meet the following criteria:

1. Your visit must be strictly for tourism purposes.

2. You must have a confirmed return ticket to show that you are flying out of Thailand within 30 days of entry, as appropriate. Open tickets do not qualify. Traveling over land out of Thailand by train, bus, etc. to Cambodia, Laos, Malaysia (including en-route to Singapore), Myanmar, etc. may be accepted as proof of exiting Thailand.
You may be asked to show your flight ticket upon entering Thailand. If you do not possess a flight ticket to show that you will be exiting Thailand within 30 days of entry, you will be most likely refused entry.

3. It will also be necessary to prove that you have funds of at least 10,000 THB or cash equivalent (about 305/USD and 410/CAD) per person during your stay in Thailand.
A fee may be levied on persons entering Thailand under the VISA EXEMPTION RULE especially when entering through a land border in Southern Thailand.