Coordinate tax filings, corporate reporting, employment obligations and operating permissions for companies in Thailand.
Part of Viettonkin's Global Company Registration services
Thailand's Board of Investment issued promotion certificates to 2,779 projects worth about THB 1.15 trillion in 2025, up 36 percent. Companies holding those certificates take on the conditions written into them, on top of Revenue Department filings and a corporate timetable that runs from shareholder approval of the accounts to filing with the Department of Business Development. Because the year-end milestones fall close together, it is easy to treat them as one deadline and miss the earlier one.
Viettonkin coordinates compliance for companies in Thailand across Revenue Department filings, corporate accounts, employment obligations and, where relevant, BOI promotion conditions. We keep each milestone separately assigned, work with the company’s accountants and HR team on the records each one needs, and retain the evidence of what was filed and approved.
Much of the pressure falls in the months after the financial year-end, when the accounts, the shareholder approval and the annual tax return depend on each other. The rest of the year has its own recurring rhythm.
During the year, VAT and withholding filings, social security contributions and employment changes form a recurring cycle. Part-way through a 12-month accounting period, the company also files a half-year corporate income tax return based on an estimate of the full year’s net profit, which needs a defensible basis because a significant underestimate can attract a surcharge.
After the year-end, the sequence tightens. Shareholder approval of the financial statements, the filing with the Department of Business Development and the annual corporate income tax return each have their own deadline, set out in the calendar below. Each needs its own preparation time, and a delay at the first step reduces the time available for the next.
Companies with BOI promotion add a further layer, because their obligations depend on the conditions and reporting requirements in their own promotion certificate. Changes to activities or ownership can also affect foreign-business permissions, which is why planned changes are reviewed against those permissions before they are implemented.
The retainer defines preparation, submission, coordination and specialist responsibilities. Where accounting, payroll or legal work stays with another provider, the scope records the hand-over points.
We scope the VAT and withholding work, the half-year corporate income tax estimate and the annual return, and agree each filing’s inputs, preparer and approver with the accounting team. Related-party transactions that need separate tax advice or documentation are identified early, so that work can be commissioned in time.
We coordinate the financial statements, shareholder approval and DBD submission with the corporate secretarial and accounting teams. Each milestone is assigned separately with its own preparation dates, which avoids the assumption that one year-end deadline covers the approval, the filing and the tax return.
We track employee changes, employer obligations and required contributions with the HR and payroll teams, and include the relevant Social Security Office and compensation-fund work in the calendar. New hires and leavers are handled through an agreed information flow rather than left to the next payroll run.
For BOI-promoted entities, we review the certificate’s conditions and reporting requirements and add them to the calendar. Foreign-business permissions and sector licences are checked against the company’s actual and proposed activities, and planned changes are reviewed before implementation.
These planning categories must be converted into a dated calendar for your entity, reporting period and current requirements. Where a date depends on the financial year-end or an approval date, the calendar works it out for your company.
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| Cycle | Workstream | Planning point |
|---|---|---|
| Recurring | VAT, withholding and employment obligations | Use the applicable filing dates and confirm any current electronic-filing extensions. |
| Half-year | Corporate income tax return | Generally within two months after the first six months of the accounting period. |
| Annual | Shareholder approval of accounts | For a private limited company, within four months after the financial year-end. |
| After approval | DBD financial-statement filing | Within one month after shareholder approval. |
| Annual | Corporate income tax return | Within 150 days after the accounting period ends; this is not simply five calendar months. |
| Certificate-specific | BOI reporting and conditions | Read the company’s own promotion certificate and current BOI instructions. |
Selected points to assess when reviewing existing processes and records. They are the areas where inherited Thai calendars most often combine separate obligations.
A provisional tax estimate needs a defensible basis. Base the estimate of full-year net profit on current results and forecasts agreed with the tax team, and revisit it if trading differs materially from the budget it was based on.
Accounts approval, DBD filing and annual tax submission have different deadlines. Schedule document preparation and management approval for each, working back from the earliest date, and agree the auditor’s timetable early because the later milestones depend on it.
Changes to operations or ownership can affect foreign-business permissions and BOI conditions. Assess them before implementing the change rather than after the new activity has begun, and keep the analysis with the company file so the reasoning is available if the question is raised later.
The same patterns tend to appear when we review a Thai company’s records. Most come from obligations managed by different people without a shared calendar.
Service fees, loans and licence payments between a Thai company and its foreign parent or affiliates may need documentation that supports the pricing, depending on the company’s size and the transactions involved. When nobody owns that documentation, the question tends to arise during a tax review rather than when the arrangement is set up, which is why related-party work is identified early and scoped separately.
Promotion conditions are sometimes held by a project team or a former adviser, separately from routine tax and corporate filings, and can be overlooked in a busy year. Reading the certificate and adding its requirements to the shared calendar keeps them visible to everyone responsible.
Hiring can move faster than HR administration, and registrations or contribution changes are then left until the next payroll cycle. An agreed information flow between HR, payroll and the compliance calendar reduces that lag and gives a clear record if employment details are queried later.
Tax settings in accounting and invoicing systems are often configured once and not reviewed when rules or the business change. Checking them at set points in the year, and whenever a relevant rule changes, avoids filing on outdated assumptions; the review can be combined with the half-year estimate.
Separate historical remediation from the routine work ahead. Routine filings should not wait while older issues are investigated, and older issues should not be hidden inside the routine calendar.
We collect registrations, licences, tax and payroll records, prior submissions and correspondence with authorities. From these we identify missing evidence and unresolved obligations and separate them from the routine work coming up. The review also shows which records other providers hold and how we will receive them.
We name the preparer, approver and submitter for each obligation. Document cut-off dates are set so approvals are not squeezed into the last days before a deadline, and dependencies on management, the auditor or other advisers are identified at this stage.
For each filing we retain the submitted version, the acknowledgement and payment evidence where relevant. Follow-up queries and changes to the agreed calendar are recorded against the obligation, so the file can support an audit, an authority review or due diligence without being rebuilt.
The calendar is reviewed when the company hires, changes ownership, adds an activity or receives an authority enquiry. Each review confirms that the scope still matches how the company operates and updates responsibilities where needed.
Coverage depends on the entity and the agreed engagement letter. The first column lists routine work to scope; the second lists work that is identified and quoted separately.
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| Routine work to scope | Specialist work to identify separately |
|---|---|
| Applicable return and reporting coordination | Full bookkeeping, audit or specialist tax advice. |
| Employer and investment compliance support | Employment disputes, tax investigations or litigation. |
| Licence tracking and agreed changes | New sector-licence applications and complex restructuring. |
| Documented compliance calendar | Historical remediation, transaction reviews or expanded entities. |
The examples below are engagements Viettonkin carried out in Vietnam, not in Thailand. They show how we approach regulatory and compliance questions for foreign investors, while work in Thailand is scoped to local requirements. Since 2009, Viettonkin has supported 2,000+ businesses, including Fortune 500 and VNR500 companies.
A Hong Kong garment manufacturer in Tay Ninh province was considering relocation to a new industrial zone in Tra Vinh. Viettonkin assessed the risks of acquiring industrial land, compared ownership structures and their tax implications, and set out the land acquisition procedure for foreign investors.
Read the case study
Two investors from China set up a joint venture company and factory in Vietnam. Under a retainership, Viettonkin advised on the legal process, compliance issues in construction and manufacturing and charter capital procedures, and supported adjustments to the Investment Registration Certificate and Business Registration Certificate.
Read the case studyPractical answers for your compliance planning.
No. The applicable obligations depend on tax status, legal form, activities, licences, workforce and reporting period. The engagement starts by mapping the company’s actual position.
Yes. The scope can assign responsibilities across your providers, with named owners for data, preparation, approvals and submission.
An initial review can establish the gaps and priorities. Any remediation, authority engagement and potential liabilities are assessed separately from ongoing routine support.
Not automatically. The engagement letter distinguishes coordination from specialist services such as statutory audit, transfer pricing advice or dispute representation.
Share the entity registrations, licences, current activities, tax and employment profile, prior filings and immediate deadlines or authority enquiries.
Regulatory points checked on 10 September 2026; market statistics checked on 11 September 2026. Requirements depend on the activity, investor and filing date.
Tell us your market, entity structure and immediate priorities. We will confirm the documents, responsibilities and scope of support.
