When most foreign shareholders set up a company in Thailand, what they first get their heads around is the annual-level rhythm: the AGM, DBD financial statements, and corporate income tax filings such as PND 50/PND 51. It’s only once they actually “hire their first employee” that they suddenly realize monthly payroll seems to involve personal income tax withholding, social security, and even workers’ compensation — without being sure exactly which day filing should start from, which forms to use, or what happens if they’re late.
On top of that, many accountants or service agents just say “we’ll file PND1 and social security for you every month” and leave it at that — the employer is left unsure whether the accounts have actually been opened correctly, when the deadlines fall, or whether not receiving a report means nothing was filed.
This article solves exactly one problem: once a company has its first employee, what are the social security and payroll tax actions a Thai employer “must” do every month?
Start With the Direct Answer
As soon as a Thai company hires its first employee who meets the social security conditions, the employer basically has to handle two tracks at once:
Social Security (Social Security Fund, SSO): register the company and the employee with social security, then each month withhold the employer’s and employee’s contributions based on salary, and file and pay by the 15th of the following month.
Payroll Withholding Tax (Personal Income Tax Withholding – PND1): calculate each employee’s withholding tax under Thai personal income tax rules, and file and pay by the 7th of the following month (e-filing generally extendable to the 15th).
If these two things are neglected, an employee may only discover they were never properly enrolled in social security when they fall ill, lose their job, or retire, while the company risks being pursued for back payments and surcharges, or even facing criminal liability or a labor dispute. Most companies have this handled by an accountant or payroll service provider, but the employer should still know, at minimum: whether social security and withholding tax registration has been completed, whether filings and payments are submitted on time every month, and whether employees receive payslips and social security proof.
Practical Checklist: What Employers Should Confirm Now
This section assumes you’re about to hire your first Thai or foreign employee (paid a Thai salary, employed in Thailand). Go through each item yourself — if you can’t answer one, it means you need to do more homework or ask your accountant.
Social Security: What to Do From the Moment You Have an Employee
Has the company completed “employer account” registration with the social security agency? Most new companies obtain a social security employer number at the same time as registering with the DBD, or must complete employer and employee registration within 30 days of having their first employee.
Has the first employee been registered as an insured person in the social security system? This generally must be done within 30 days of employment, using a designated form (such as SSO 1-03 or the equivalent online form).
Do you know the fixed monthly rhythm for social security filing and payment? As a common example for 2025–2026, the employer and employee each contribute about 5% of salary as social security, calculated on a salary base, filed and paid by the 15th of the following month; the actual rate and cap should follow the current year’s official announcement.
Have you confirmed who is responsible for filing and payment every month? Is it in-house HR, an accounting firm, or a payroll outsourcing provider? You should have seen at least one social security filing receipt or payment slip proving it was actually done.
Payroll Withholding Tax: What PND1 Requires Every Month
Does the company have withholding tax filing eligibility and a tax ID (usually a 13-digit company tax number)?
When paying salaries, has each employee’s monthly withholding tax been calculated under the personal income tax rules? Employers must calculate this using the official rates and deduction rules — you can’t just pick a percentage. Many companies leave this to an accountant or an automated payroll system, but the employer should know whether it’s actually being withheld.
Is someone filing PND1 and paying it before the deadline in the following month? The common paper-filing deadline is the 7th of the following month; e-filing generally extends this to the 15th — the actual date follows the current year’s announcement.
Do employees receive a payslip that clearly lists salary, social security and withholding tax? If employees have no idea what’s being deducted, the employer will find it hard to explain things if a tax or social security dispute arises later.
Things to Watch Out For
When talking with an accountant, agent or HR, be on alert if you hear any of the following:
“You only have one or two people right now, no rush on social security — do it once you have more staff.” Social security law is, in principle, “the moment you have your first employee, they must be enrolled” — you can’t put it off indefinitely just because headcount is small.
“We’ve been filing your taxes, we just haven’t specifically shown you the documents.” If there is no PND1 or social security payment receipt, report screenshot, or government system confirmation over an extended period, there’s no way to confirm whether filing has actually happened.
“If the employee wants social security, we can just add them later.” Social security registration has a time limit; during a period of late registration the employee may be considered uninsured, which can also affect their entitlement to benefits.
“We only handle your annual tax (PND 50) — you handle the monthly withholding tax yourself.” If no one inside the company is actually managing PND1, monthly payroll withholding tax may be seriously behind, building up risk.
“We filed based on the amount you gave us, so no additional tax was withheld.” If the accountant simply treats the “net salary” you provided as the “salary reported to the tax authority,” without actually withholding or filing tax, this can later be found to be underreported income.
What to Decide Next
When you can go ahead and continue hiring and paying salaries:
You know the company has obtained its social security employer number, the first employee is registered in the social security system, and you’ve seen the relevant application form or online system screenshot; you’ve confirmed social security filing and payment are completed before the deadline every month, and you can obtain the receipts or transaction records; your accountant or HR can explain the logic behind the withholding tax calculation and regularly provides PND1 filing records or e-filing confirmations; employees receive a payslip every month clearly listing salary, tax withheld and social security deducted, matching the company’s books.
When you should stop and verify first:
The company has been established for a long time, but no one has ever mentioned a social security employer account, and you’ve never seen any social security receipts or documents; the accountant says “don’t worry, we’re handling it” but cannot provide any recent proof of PND1 or social security payments; employees report that their social security record cannot be found at a hospital, when job-hunting, or during other administrative procedures; some employees are paid “cash salaries” that are not reflected in the company’s books at all, with no corresponding withholding tax or social security deduction.
If you run into these situations, it’s advisable to pause further hiring or salary adjustments, and ask an accountant or lawyer familiar with Thai payroll and compliance to help review which months were not filed, whether late filing and payment are possible, and whether you need to communicate with employees about correcting any gap in their past social security coverage.
FAQ
Q1: If we only have foreign employees, no Thai employees, do we still need to handle social security and withholding tax?
As long as an employee is employed in Thailand and receives a Thai salary, personal income tax generally still needs to be withheld and social security registration and payment handled as required. Whether an exception applies depends on their work visa, employment relationship, and how social security law applies — a professional advisor should judge this based on the specific circumstances.
Q2: My company just registered and received an employer number from the social security agency — does that mean everything is automatically taken care of?
In most cases, the system has only set up your employer account for now. When you actually hire employees, you still need to complete each employee’s registration and the monthly filing and payment within the statutory time limit — you cannot assume that “having a number means already being insured.”
Q3: If we haven’t filed social security or withholding tax for employees for the past few months, should we file late?
Prolonged non-filing can result in the tax and social security authorities pursuing back payments plus interest and penalties, and can also leave employees under-protected on the social security side. It’s advisable to have a professional accountant or lawyer review, as early as possible, whether late filing and payment are possible, and assess how to communicate with employees and keep an internal record of the process.
For case-specific payroll situations, consult a professional familiar with Thai payroll and compliance; for general questions about how the system works, ask Zagdim.
Disclaimer
This article provides general information only on “the practical monthly social security and payroll withholding tax obligations a Thai employer takes on once it has its first employee.” It does not cover the complete Thai labor law, tax law and social security system, and does not constitute legal, tax or accounting advice. The rules that actually apply can change depending on employee status, contract type, place of work, annual policy, and updates to e-filing systems. Before making any major decision or filing anything retroactively, consult a professional familiar with Thai regulations.
Have a question about this guide? Leave a comment below, or ask Zagdim directly.
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Sources
- Thai Social Security Office – Employer and Employee Registration Guidelines
- Thailand Revenue Department – Personal Income Tax and Withholding Tax Filing Information
- Acclime Thailand – Social Security in Thailand Guide
- HR Forte – Thailand Payroll and Social Security Overview
- MBMG Group – FAQ About Social Security in Thailand
- HLB Thailand – Employer Social Security Registration Procedures
