HR & Payroll for Thai Manufacturing: BOI, Shifts, Compliance

A Thai factory runs on three clocks. The production clock, which never stops. The labour law clock, which caps how long anyone can work. And the payroll clock, which turns every shift, premium and absence into a number that must be right by the 7th or the 15th.

For manufacturers promoted by the Board of Investment (BOI), there is a fourth: the rules for the foreign experts who help run the line.

This guide brings the four together.

Editorial image for HR and payroll for Thai manufacturing: BOI incentives, shift complexity and compliance

BOI promotion: what it means for HR

Most BOI incentives sit with finance: corporate income tax exemptions and import duty relief. The one HR feels directly is the right to bring in foreign talent.

Under Sections 25 and 26 of the Investment Promotion Act, BOI-promoted companies may bring in foreign skilled workers and experts, along with their spouses and dependants, and those personnel receive work permits for the positions BOI approves. (BOI) Section 24 allows foreign nationals to enter before the promotion certificate is issued, for example to study the investment. (BOI)

The process runs in two stages through BOI’s Single Window for Visa and Work Permit system. First, BOI approves the position. Then the company applies to place a named person in it. The person must enter Thailand on a Non-B visa and hold qualifications and experience that match the approved role; family members enter on a Non-O visa. (BOI)

For HR, the practical point is that a BOI work permit is tied to an approved position. Promote, transfer or re-title a foreign expert, and the approval may need to change too.

Working hours and overtime: the shift-planning constraints

The Labour Protection Act sets the limits every roster must respect. BOI’s own investor guidance summarises them. (BOI One Start One Stop)

Rule	Limit
Normal work	8 hours a day, 48 hours a week
Hazardous work	7 hours a day, 42 hours a week
Make-up hours	Up to 9 hours on another normal day, within 48 hours a week, by agreement
Weekly holiday	At least 1 day, at intervals of no more than 6 days
Overtime and holiday work	No more than 36 hours a week
Overtime rates	From 1.5 times to 3 times the normal hourly rate
Consent	Employees choose whether to work overtime or on holidays

The 1.5 times rate applies to overtime on a working day. Work on a holiday within normal hours is paid at a higher rate, and overtime on a holiday at 3 times. (BOI One Start One Stop)

Two features make manufacturing harder than office payroll. First, hazardous work changes the definition of a normal day, so the same rotating shift can produce overtime for one line and not another. Second, the 36-hour cap combines overtime and holiday work, so a public holiday week can push a line over the limit even when daily overtime looks modest.

Minimum wage: set by province

Thailand has no single national minimum wage. Daily rates since 1 July 2025 run from THB 337 to THB 400 depending on province. The THB 400 rate covers Bangkok, Chachoengsao, Chonburi, Phuket, Rayong and Ko Samui. (DLA Piper)

The controlling schedule is Wage Committee Notification No. 14, dated 17 June 2025 and effective from 1 July 2025; areas it did not change remain on Notification No. 13. (Government Public Relations Department) Rates verified on 28 October 2026; check each site’s province, and any sector-specific rate, against the full schedule before publication.

Three of the six THB 400 areas, Chachoengsao, Chonburi and Rayong, form the Eastern Economic Corridor, Thailand’s main industrial investment zone. A multi-site manufacturer may pay different statutory floors at plants an hour apart.

Employer and employee each contribute 5% of wages to the Social Security Fund. From 1 January 2026, the wage ceiling rose from THB 15,000 to THB 17,500, so the maximum contribution rose from THB 750 to THB 875 a month for each party. (Baker McKenzie)

The ceiling rises again in two steps.

Period	Monthly wage ceiling	Maximum contribution per party
1 January 2026 – 31 December 2028	THB 17,500	THB 875
1 January 2029 – 31 December 2031	THB 20,000	THB 1,000
From 1 January 2032	THB 23,000	THB 1,150

Source: KPMG Thailand. The ministerial regulation was published in the Royal Gazette on 12 December 2025. (DLA Piper)

Because contributions reduce taxable income, the higher ceiling also changes monthly tax withholding.

The Employee Welfare Fund: now 1 January 2027

The Employee Welfare Fund has been postponed again. Collection of contributions moved from 1 October 2026 to 1 January 2027, under a royal decree published in the Royal Gazette on 22 October 2026, as reported by DLA Piper on 23 October 2026. (Bloomberg Law)

Subject to the applicable implementing regulations, employer and employee are each expected to contribute 0.25% of wages from 1 January 2027 to 31 December 2031, rising to 0.5% each from 1 January 2032. (Mondaq / DLA Piper)

Coverage is generally reported to apply to employers with at least 10 employees, again subject to the implementing regulations. (Bloomberg Law) Those with a provident fund or comparable benefits should review whether they qualify for exemption. (Lockton)

The extra three months are a gift. Use them to confirm which payments count as wages for the fund.

The monthly and annual filing cycle

Obligation	Deadline
PND 1 withholding tax	7th of the following month on paper; 15th if filed electronically
Social security contributions	15th of the following month
Employee Welfare Fund	From the January 2027 wage month
PND 1 Kor annual return	By the end of February (28 February 2027), under section 58(2) of the Revenue Code; check any Revenue Department e-filing extension before relying on it
Form 50 Tawi to employees	By 15 February for salary payments under section 50(1) (Revenue Code, section 50 bis)

The 7th and 15th PND 1 dates apply to withholding returns generally. (Forvis Mazars) Social security contributions are due by the 15th of the following month. (Forvis Mazars Payroll Flash, December 2025)

The Revenue Department states that PND 1 Kor is filed once a year under section 58(2) within February of the following year. (Revenue Department) Section 50 bis of the Revenue Code requires withholding certificates for salary payments to be issued by 15 February of the following year. (Revenue Code, section 50 bis)

Where manufacturing payroll breaks

Not in the rates. In the time data.

A payroll engine can apply 1.5 times or 3 times correctly only if it knows which hours were normal, which were overtime, which fell on a holiday and which line was classed as hazardous. On a three-shift plant, that classification changes by the hour.

The fix is to connect rostering, time and attendance and payroll so the same record drives all three. That is the standard to apply when assessing any manufacturing payroll system in Thailand.

FAQs

How much overtime is allowed in Thailand? Overtime and holiday work combined must not exceed 36 hours a week.

What are the working-hour limits for hazardous work? Seven hours a day and 42 hours a week, against 8 and 48 for normal work.

What is the social security wage ceiling in 2026? THB 17,500 a month, giving a maximum contribution of THB 875 each for employer and employee.

When does the Employee Welfare Fund start? Contribution collection starts on 1 January 2027. Rates and coverage are subject to the applicable implementing regulations.

How do BOI-promoted companies hire foreign experts? BOI first approves the position, then the company applies through the Single Window for Visa and Work Permit system to place a named person, who must hold a Non-B visa.

When is PND 1 due? By the 7th of the following month on paper, or the 15th if filed electronically.

What is the minimum wage in Thailand? It is set by province, from THB 337 to THB 400 a day.