All license plates are rectangular, with variations in size and color according to the class of the vehicle. Most plates prominently display the vehicle registration ID, which usually consists of Thai letters and a number string. The province of registration is shown below the ID. The letters are embossed, and all plates must also be embossed with a seal bearing the letters "ขส". The current designs are regulated by the notification of the Department of Land Transport dated B.E. 2554 (2011 CE) for buses and trucks, and by the ministerial regulation issued B.E. 2554 for other motor vehicles.
General plates Plates for cars, vans, pick-up trucks, motorised tricycles, trailers, road rollers, tractors and agricultural vehicles follow the same design. They are in size, with a coloured and embossed outline. The registration ID consists of two series letters followed by a serial number string of up to four digits, from 1 to 9999, without leading zeroes, e.g. "กข 1" or "กข 1234". A leading digit may be added in front of the two letters if the letter pool has been exhausted, as is the case in Bangkok since 2012, giving the format "1กข 1234". Due to the case, the new plates, since 2012, have reduced text size, to keep the plate size. The province of registration is displayed in Thai underneath the registration ID, with the exception of
Yala Province which cars can also register at
Betong District, due to its distant proximity from
Mueang Yala District where the administrative offices are located. The colors of the text and background depend on the type of vehicle, and are given in following table: certain serial numbers in each series are made available for auction. These include single-digit numbers (1); twin (11), triplet (111) and quadruplet (1111) numbers, round thousands (1000); straight three-digit (123) and four-digit (1234) numbers; and pairs of two like numbers (1122, 1212, 1221). are only in private passenger car type until 2014, when private pick-up and private van auction plates are made available. In 2014, the highest price paid at auction for a vanity plate was set at 25,000,000 baht (about US$771,000) for a Bangkok plate "1กก 1111 กรุงเทพมหานคร". Because of its very high price, DLT allowed the buyer to design the background image. On October 10, 2020, the new record was set at 28,100,000 baht (about US$935,000) for "8กก 8888 กรุงเทพมหานคร". On December 10, 2022, the auction of 9กก group plates of Bangkok took place, and the new record was set at 45,090,000 baht (about US$1,300,000) for "9กก 9999 กรุงเทพมหานคร". In 2021, the Department of Land Transport confirmed the plan to release personalized plates for private passenger car type via auction. The serial letters can be a word or a person name in the
Thai script: longer than 2-3 letters in the standard plates, and vowel and tone symbols can be used. The first auction of special plates took place in Bangkok on April 7, 2022, with 84 Bangkok special plates, most of them are auspicious words and numbers, and few of them are names or nicknames with numbers.
Series letters Series letters are specific to vehicle classes, after the combinations starting with two letters are exhausted, a number is put before the letters: for example
1กก,
1กข... Private cars begin with (in order of adoption)
ก,
ข,
ง,
จ,
ฉ,
ธ,
ฐ,
พ,
ภ,
ว,
ศ,
ษ,
ส,
ช,
ฌ,
ญ,
ฎ and
ฆ (in Bangkok
กก (
1ก of old style plates) -
พล (
9ณ of old style plates) are used for change from old style plate to new style plate). Old style private cars plates begin with (in order of adoption)
ก,
ข,
ค,
ง,
จ,
ฉ,
ช,
ธ,
ว,
อ,
ฮ,
ฐ,
ศ,
ฬ,
ษ,
ณ. Private Pick-up trucks begin with (in alphabetical order)
ฒ,
ณ,
ต,
ถ,
บ,
ป,
ผ,
ย,
ร and
ล. Private vans begin with
น,
ฬ,
อ and
ฮ. Public taxis begin with
ท (in order of
ทค,
ทง,
ทจ,
ทฉ,
ทต,
ทท,
ทธ,
ทน,
ทพ,
ทม,
ทย,
ทร,
ทล,
ทว,
ทศ,
ทษ,
ทส,
ทห,
ทฬ,
ทอ and
ทฮ), (
ทก,
ทข are for permanently licensed private non-meter taxis, currently stopped license for these types of taxis). Public Yellow-green taxis begin with
ม (in order of
มก,
มข,
มค,
มง,
มจ,
มฉ,
มช,
มฎ,
1มก,
1มข,
1มค,
1มฆ). Public mini truck taxis for public transportation begin with
ฟ. Public Tuk-Tuk taxis beginning with
ศ (only
ศข) and
ส (only
สก,
สข). Some beginning with
ฌ,
ณ with green background and white text are used by service vehicles. Trailers, road rollers, tractors and agricultural vehicles, including
rot i-taen (Thai farm trucks), have
ซ as their first series letter, or
ฆ for some provinces. Each new letter pair is announced by the DLT. Each provincial registrar accordingly registers new vehicles under its latest available letter pair until all 9,999 numbers have been exhausted, then moves onto the next series letter. Letters whose appearance may be confused are skipped, and so are letter pairs which form words with bad meanings. For example, the combinations "ชน" and "ตด" are not used, as they form words meaning "crash" and "fart".
Historical designs Although license plates have likely been used since the promulgation of the Motor Vehicle Act, Rattanakosin Era 128 (1910 CE), the earliest legislation of which details are available is from 1967. The size of license plates was specified at 11 by 39 centimeters, with white text on a black background. A two-letter abbreviation of the province name, arranged vertically, was displayed to the left, and the registration ID, consisting of either a five-digit serial number or a single series letter and a four-digit serial number, was displayed to the right, e.g., "(ก.ท.) 01234" or "(ก.ท.) ก-0123". This was changed in 1975 to black-on-white plates with a size of 15 by 30 centimeters. The series identifier for Bangkok was also changed to consist of one-digit number plus one letter, e.g., "1ก-0123". The province name was given in full under the ID, as in the current system. The serial number was displayed with leading zeros, which were dropped, along with the dash, when the current format was adopted in 1997.
Motorcycle plates Plates for motorcycles are 17.2 by 22 centimeters, with an outline. Information is displayed in three horizontal rows. The series letters and leading number is displayed on the top row, and a serial number of up to four digits on the bottom row, e.g. "1กข 1234". The province of registration is shown on the middle row. The lettering is done in black, with a white background for private motorcycles and a yellow background for hired motorcycles.
Diplomatic vehicle plates License plates issued to members of diplomatic missions, international organizations or United Nations specialized agencies based in Thailand are 11 by 38.7 centimeters in size, with the format "ท 01 - 1234". On the top left is a letter denoting the status of the registrant ("ท" for diplomatic agents, "พ" for members of special embassy agencies, "ก" for consular agents, and "อ" for international organizations or United Nations agencies). On the bottom left is a number code denoting the country or organization. On the right is a serial number string of up to four digits, with a separating horizontal line in the middle. Motorcycle plates have a similar appearance but with a size of . Plates issued to diplomatic agents are colored black on white, those issued to honorary consuls are black on gray, and others are white on light blue.
Bus and truck plates License plates for buses and trucks are separately regulated, and have a size of . They show the registration number which consists of two series digits and four serial digits (with leading zeros), separated by a horizontal line. The word THAILAND is displayed in capital letters above the number. The province of registration is displayed below the number, with the "ขส" seal to the left. A numerical provincial code is shown in the top right. The text is colored black, with a yellow background for hired vehicles and a white background for private vehicles. ==Legal requirements==