Ordinary passport holders of many Western and Asian countries, including most ASEAN countries, Australia, Canada, most European Union countries, Hong Kong, Japan and the United States do not need a visa if their purpose of visit is tourism. Visitors receive 30-day permits (except for citizens of Korea, Argentina, Brazil, Chile and Peru who get 90 days), but effective 31 Dec 2016, an exemption is granted only twice per calendar year when not arriving by air. Citizens of Myanmar may enter without a visa for 14 days only if they enter by air; entry through any other mode of transport requires a valid visa. Thai immigration requires visitors' passports to have a minimum of 6 months validity and at least one completely blank visa page remaining. Visa-on-arrival is available at certain entry points for passport holders of 21 other nations (Andorra, Bhutan, Bulgaria, China, Cyprus, Ethiopia, Fiji, India, Kazakhstan, Latvia, Lithuania, Maldives, Malta, Mauritius, Papua New Guinea, Romania, San Marino, Saudi Arabia, Taiwan, Ukraine, Uzbekistan). Check the latest information from the Ministry of Foreign Affairs.
Those with passports from countries not widely known, including European city-states, or that have problems with document forgery, should obtain a visa in advance from the nearest Thai embassy. This is true even if visa on arrival is permitted. There are reports of tourists being detained using valid passports not commonly presented in Thailand. In addition, ask for a business card from the person or embassy which granted the visa, so they may be contacted on arrival, if necessary. Anyone whose nationality does not have its own embassy in Bangkok, should find out which third country represents your interests there, along with local contact information.
Those arriving via air from most African and South American countries are required to show yellow fever certificates and receive a stamp on their entry forms from the onsite health centre prior to clearing immigration.
Proof of onward travel, long happily ignored by Thai immigration, has been known to be strictly applied in some instances. Airlines, that have to pay for your return flight if immigration doesn't let you in, are more rigorous about checking for it. A print-out of an e-ticket on a budget airline is sufficient to convince the enforcers, but those planning on continuing by land may have to get a little creative. Buying a fully refundable ticket and getting it refunded once in Thailand is also an option. Land crossings, on the other hand, are a very straightforward process and no proof of onward journey required (unless the border officials decide otherwise).
Overstaying in Thailand is risky. If you make it to Immigration and are fewer than 10 days over, you'll probably be allowed out with a fine of 500 baht per day. However, if for any reason you're caught overstaying by the police you'll be carted off to the notoriously unpleasant illegal immigrant holding pens and may be blacklisted from Thailand entirely. For most people it's not worth the risk: get a legal extension or do a visa run to the nearest border instead. Now that the number of visa exemptions at land borders is limited it is even more attractive to visit an immigration office to extend your visa or visa exemption with 30 days.
Thai immigration officers at land border crossings are known to ask foreigners for bribes of about 20 baht per person before they stamp your passport. Immigration officers at airports generally do not ask for bribes.
It's controversial whether you must carry your passport with you at all times, but police are known to have tried to extort bribes for this. In some situations it has proven to be enough to carry a photocopy of the passport ID page and the page with the latest entry stamp.
The main international airports in Thailand are at Bangkok (BKK IATA) and Phuket (HKT IATA), which are well-served by intercontinental flights. Practically every airline that flies to Asia also flies into Bangkok, meaning that there is plenty of competition to keep ticket prices down. Be aware, Bangkok as two major airports: Suvarnabhumi Airport (BKK IATA) which serves most larger carriers and is the main airport and the smaller Don Mueang International Airport (DMK IATA) which primarily serves low-cost carriers both internationally and domestically.
International airports are also located at Hat Yai, Krabi, Ko Samui and Chiang Mai, though these are largely restricted to flights from other Southeast Asian countries. Kuala Lumpur and Singapore make excellent places to catch flights into these smaller Thai cities, meaning you can skip the ever-present touts and queues at Bangkok.
The national carrier is the well-regarded Thai Airways, with Bangkok Airways filling in some gaps in the region. Bangkok Airways offers free Internet access while you wait for boarding to start at your gate. Thai Airways subsidiary Thai Smile (low cost carrier) has also started international operations from India. In addition, Malaysian discount carrier AirAsia has also set up a subsidiary in Thailand, and is often the cheapest option for flights into Thailand.
Chartered flights from and to Thailand from international destinations are operated by Hi Flying group. They fly to Bangkok, Phuket, Ko Samui and Udon Thani.
For a full at-a-glance list of all Thai-based carriers, see the Thai airlines section (below).
Cambodia - six international border crossings. The highway from Siem Reap and the temples of Angkor via Poipet to Aranyaprathet, once the stuff of nightmares, is now merely bad and can usually be covered in less than 3 hours. However, the queues at the Poipet crossing are infamous; the other crossing like Koh Kong / Hat Lek on the southern route from Sihanoukville to Trat are much quieter and less stressful. The land borders close for the night.
Laos - the busiest border crossing is at the Friendship Bridge across the Mekong between Nong Khai and the Lao capital Vientiane. It's also possible to cross the Mekong at Chiang Khong / Huay Xai, Nakhon Phanom / Tha Khaek, Mukdahan / Savannakhet, and elsewhere.
Malaysia and Singapore - driving up is entirely possible, although not with a rented vehicle. Main crossings (with the name of the town on Malaysian side in brackets) between Thailand and Malaysia are Padang Besar (Padang Besar) and Sadao (Bukit Kayu Hitam) in Songkhla Province, Betong (Pengkalan Hulu) in Yala Province, and Sungai Kolok (Rantau Panjang) in Narathiwat Province. There are regular buses from Singapore to the southern hub of Hat Yai.
Myanmar - The border crossings with Myanmar are located at Mae Sai/Tachileik, Mae Sot/Myawaddy, the Three Pagodas Pass (Sangkhlaburi/Payathonzu) and Ranong/Kawthoung. As of 2013, the Burmese government has lifted all restrictions on foreigners entering and leaving Myanmar via the Thai border, so it is now possible to travel between Yangon and Bangkok overland. Just make sure that both your Thai (if required) and Burmese visas are in order, as no visa-on-arrival is available at the border.
As traffic moves on the left in Thailand, but moves on the right in all the neighbouring countries except Malaysia, you will generally need to change sides of the road when crossing an international border into Thailand.
Thailand's sole international train service links to Butterworth (near Penang) and Kuala Lumpur in Malaysia, continuing all the way to Singapore. Tickets are cheap even in first class sleepers, but it can be a slow ride. What is a 2-hour flight to Singapore will take you close to 48 hours by rail, as you have to change trains twice. The luxury option is to take the Eastern & Oriental Express, a refurbished super-luxury train that runs from Singapore to Bangkok once per week, with gourmet dining, personal butler service, and every other colonial perk you can think of. However, at around USD1,000 one-way just from Bangkok to Butterworth, it is approximately 30 times more expensive than an ordinary first-class sleeper!
While you can't get to Laos or Cambodia by train, you can get very close, with rail terminals just across the border at Nong Khai (across the river from Vientiane) and Aranyaprathet (for Poipet, on the road to Siem Reap). A link across the Mekong to Laos opened in March 2009, but service to Cambodia remains on the drawing board.
There are no rail services to Myanmar, but the Thai part of the infamous Burma Death Railway is still operating near Kanchanaburi.
It is possible now to travel by ferries in high season (Nov-May) from Phuket and island hop your way down the coast all the way to Indonesia.
This can now be done without ever touching the mainland,
Phuket (Thailand) to Penang (Malaysia), islands en route:
The Thai portion can be done in a day.
Ferries cross from Satun in southern Thailand to the Malaysian island of Langkawi, while over in Narathiwat Province, a vehicular ferry shuttles between Tak Bai and Pengkalan Kubur, near Kota Bharu in Malaysia's Kelantan state.
There are also occasional cruises from Malaysia and Singapore to Phuket and Bangkok, the main operator being Star Cruises, but no scheduled services.