A foreigner is allowed to perform any type of work (as long as it is not prohibited by the law) and in any location in relation to the current employer without requesting an approval from the Registrar.

The employer must notify labor officials within 15 days from the date of employment and within 15 days after the termination of employment, if any foreign employee ceases to work for whatever reason. The foreign employee must also notify labor officials within 15 days from the date of employment, as well as every time he changes the employer. 
Noncompliance of the employer/employee will be subject to a fine of up to 20,000 Baht.

Any foreigner who cannot show his Work Permit booklet upon the officer or Registrar’s request may be subject to a maximum fine of 5,000 Baht.

Any foreigner engaging in work without a valid Work Permit, may be subject to a fine ranging from 5,000 Baht to 50,000 Baht. If the foreigner has a Work Permit but engages in any prohibited work, he may be subject to a fine of 5,000 Baht to 50,000 Baht.
If a foreign national works or provides services on a matter which is deemed urgent and necessary without notifying the labor authority, the foreign employee may be liable for a fine of maximum 50,000 Baht.

An employer who hires or allows a foreigner to work without a valid Work Permit may be punished with a fine from 10,000 Baht up to 100,000 Baht for each foreign employee.
The employer who repeat the offense will be liable for fines of 50,000 Baht to 200,000 Baht per employee, or imprisonment for maximum one year, or both. In addition, such employer will be prohibited from employing foreigners for a period of three years from the date of the final court judgment.

An employer who allows a foreigner to engage in any prohibited work may be punished with a fined of 10,000 Baht to 100,000 Baht.