If you're over 18 and have a valid International Driving Licence or a driving licence from your home country, you'll need the following original documents plus signed photocopies of each:

Your existing licence translated into English (if not already in English) and approved by your embassy.

1. Your passport with a current valid Non-Immigrant Visa - copies of the main page plus the visa page, the last entry stamp page and the entry/exit card. (Documentation from some offices indicates that Tourist Visas may be accepted, but please check this with the Land Transportation Department office locally.)
   
2. You'll also need a certificate of your present address in Thailand, usually available from The Thai Immigration Office on presentation of your passport. A certification of your address from your embassy, or as shown on your work permit, may also accepted.
   
3. 2 photographs (1 inch square)
   
4. A medical certificate not more than 1 month old (available from any doctor for a small fee).

Your first Thai driving licence will be valid for one year; on renewal you'll be issued with a 5-year licence. To renew, you'll need your expiring Thai driving licence plus items 2- 5 above. A 1-year licence cannot be renewed until the date of expiry (this means that, if your licence expires on a Saturday or Sunday, you cannot renew on the Friday before you must refrain from driving over the weekend! A 5-year licence, however, can be renewed up to 14 days before expiry.

If you have all the documentation above, you won't need to take either the written 'knowledge' test or the practical driving test. You will, though, have to take the 'eye' test - a somewhat bizarre experience. We recommend that you find someone who has experienced this within the last year or two, and get the low-down...

If you don't have a valid International Licence, or that of your home country, you'll be required to undertake a short period of instruction followed by a 'knowledge' (Highway Code-type) and a 'driving' test on a short (off-road) route.

This can take a few hours and we suggest:

• Bring a Thai language speaker with you as an interpreter; this will help you complete the Thai language forms and speed up the process.
  
• Arrive before 9.30 am (8.30 am is safer as, if the training class is over-subscribed, you'll have to return on another day).
  
• Bring a pen and the licence fee (55 baht for motorbike or 105 baht for car) and the documents described in 2-5 above.

Here's what will happen:

• That eye test (actually, it's more about co-ordination).
  A period of training in Thai (training aids in English are usually available).
  
• The knowledge test (in some places a written multiple choice test, but in others a computer-based multiple choice test).
  
• A break for lunch, usually 12 noon-1.00 pm (before which you'll be told if you've passed the knowledge test).
  
• If you pass the knowledge test, next comes the 'driving' test - over a short course at the licensing centre. This includes reversing into a confined space, various turns and a hill start.
  
• If you make it through this, you can take your papers to the administration office, pay the fee and - if it's not yet 3.30 pm - you can usually collect your completed licence on the same day; if after 3.30 pm, you'll probably need to come back the next day to collect your licence.

As with all such procedures, patience will be your strongest virtue on the day.