Reviewed by ThaiLawOnline, a licensed Thai law firm practising in Thailand since 2006. Thai lawyer of record: Wichuda Atthamethakon, LL.M., Thai Bar Licence 3149/2556.
Last updated on September 5, 2026
Probation period (ทดลองงาน, thot long ngan, also written probationary period) is a trial period at the start of employment during which the employer assesses a new hire before confirming the position. The Labour Protection Act B.E. 2541 does not mention probation and gives it no special status: an employee on probation is an employee, covered by minimum wage, social security, working-hour limits and, above all, the notice rule in Section 17 and the 120-day severance threshold in Section 118. Thai practice fixes probation at 90 to 119 days for exactly that reason.
Table of Contents
What the law says, and does not say
Probation exists only because the contract creates it. Its length, any extension, and the criteria for confirmation are matters of agreement. What the contract cannot do is switch off the statute. An indefinite contract is indefinite from the first day, so ending it during probation is a termination under the Labour Protection Act, requiring one pay period of written notice or pay in lieu unless a Section 119 cause exists. Courts have held that a probation clause does not turn the contract into a fixed-term one.
Severance under Section 118 starts at 120 days of continuous service. Termination on or before day 119 therefore costs notice pay but no severance; termination on day 120 costs 30 days’ wages as well. Extending probation does not stop the count, since the days are still days of service.
Practical points for a foreign employee
Same rights from day one. Full agreed salary, social security registration within 30 days, overtime, sick leave and public holidays all apply during probation. Annual leave accrues but is exercisable after the first year unless the contract says otherwise. The work permit and extension of stay are already issued for the full term, so probation has no immigration effect, but a termination during it does.
The 119-day practice. Employers who want to keep the option of parting without severance end probation before day 120, and the notice must be timed so that the last day, not just the letter, falls before the threshold. The common mistake on the employee side is accepting that no notice is due during probation; it is, and pay in lieu can be claimed at the labour inspector’s office or the Labour Court. The employee rights guide sets out the surrounding rules.
Before and after day 120
The numbers show why 119 is the figure employers use.
| Item | Day 1 to 119 | Day 120 onwards |
|---|---|---|
| Notice under Section 17 | One pay period, or pay in lieu | One pay period, or pay in lieu |
| Severance under Section 118 | None | 30 days’ wages, rising with service |
| Unused annual leave pay | Per contract | Pro rata for the year |
| Unfair dismissal claim | Possible, but courts give weight to the probation purpose | Possible |
| Section 119 dismissal for cause | No notice, no severance | No notice, no severance |
A termination letter during probation should still state the reason. An employer that simply writes failed probation has given a reason; one that gives none may find the Labour Court asking for it later.
Frequently asked questions
How long is a probation period in Thailand?
There is no statutory length. Most contracts use 90 to 119 days, because severance under Section 118 becomes payable at 120 days of continuous service. A longer probation is lawful but gives the employer no advantage after day 120.
Can an employer in Thailand terminate during probation without notice?
No, unless a Section 119 cause such as dishonesty or three days’ unexplained absence exists. An ordinary probation termination needs one pay period of written notice or the equivalent pay in lieu, because the contract is indefinite from the start.
Is severance pay due if I am terminated during probation in Thailand?
Not if the termination takes effect before 120 days of service. From day 120, 30 days’ wages are due even if the contract still calls the employee probationary. Notice pay is due in both cases.
See also: notice period and pay in lieu, severance pay, employment contract, termination of employment, and the guides on employee rights in Thailand and employment law for employers.
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