Accounting Requirements in Thailand, Explained (2026 Guide).

Who the accounting requirements in Thailand apply to

The accounting requirements in Thailand come from one statute: the Accounting Act B.E. 2543 (2000). Section 8 puts the accounting duty on every registered partnership, limited company and public limited company established under Thai law, on juristic persons established under foreign law but operating business in Thailand, and on joint ventures under the Revenue Code.

There is no small-company carve-out and no dormancy carve-out. If your company exists on the register, it carries the duty. The Act calls this entity the "person charged with the accounting duty", and that person is the company itself, acting through its directors.

The duty starts early. Under Section 9, a Thai partnership or company must begin accounting from the date it is registered as a juristic person. If you are setting up a company in Thailand as a foreigner, the bookkeeping obligation begins on registration day, months before the first tax return is due.

What "keeping books" means under the Act

Keeping books means maintaining accounts that reflect reality, backed by documents, on an annual cycle. Three sections do the work:

• Section 10 requires the first closure of accounts within twelve months of the start of accounting, and a closure every twelve months after that. This creates the company's accounting period.
• Section 12 requires the company to properly and fully furnish its accountant with the supporting documents used for making entries, so the accounts reflect the real operation and financial position in line with accounting standards.
• Section 20 puts a mirror duty on the accountant: prepare accounts that reflect the actual results and financial position, with proper and complete supporting documents behind every entry.

Read together, the standard is documentary. Every entry needs a paper trail: invoices, receipts, contracts, bank records. A ledger reconstructed at year-end from bank statements, with no underlying documents, fails the Act's own test even if the totals happen to be right.

The Thai language rule

Accounting entries must be made in Thai. Section 21 allows two alternatives: entries in a foreign language with the corresponding Thai attached, or entries in accounting codes accompanied by a code translation manual in Thai.

That is the whole rule. Foreign owners often hear that the books must also be kept in baht; the Act's text states the language requirement and says nothing about currency, so treat any currency claim as practice rather than statute and let your accountant confirm what the Revenue Department expects for tax computation.

In practice, accounting firms run the statutory ledger in Thai and produce English management reports alongside it. That satisfies Section 21 and still gives a foreign director numbers they can read.

Who can be the bookkeeper

Not just anyone. Section 19 requires the company to provide an accountant who possesses the qualifications prescribed by the Director-General of the Department of Business Development, and makes the company responsible for supervising that accountant so the accounts reflect reality.

The detailed qualification rules sit in notifications issued under the Act rather than in the Act itself, and they tie required credentials to the size of the company. The practical consequences are two. First, a director without the prescribed accounting qualifications cannot simply keep the company's books personally; the Act's self-bookkeeping allowance applies to natural persons charged with the duty, not to company directors. Second, engaging an accounting firm does not transfer the duty: the company remains the person charged with it, and the company answers for the accountant's work.

How long records must be kept, and where

Five years minimum. Section 14 requires accounts and supporting documents to be retained for not less than five years from the date of the account closure, and the Director-General can extend that for particular types of undertaking to a period of up to seven years.

Section 13 adds a location rule that surprises many owners: the accounts and supporting documents must be kept at the company's place of business, its regular production or storage site, or its regular office, unless the Accounting Inspector permits another location. Records kept on a computer at another place in Thailand, linked to the place of business, count as kept at the place of business. Shipping the paper archive to a director's home abroad does not.

Annual financial statements and the five-month rule

Every accounting year has to end in a financial statement filed with the authorities. Section 11 sets two clocks:

• A registered partnership, a foreign juristic person operating in Thailand or a Revenue Code joint venture must prepare a financial statement and submit it within five months from the date of closure of accounts.
• A limited company or public limited company must submit within one month from the date the financial statement is approved at the general meeting. Since the Civil and Commercial Code drives the meeting timetable, the audited statement, the shareholders' meeting and the filing form one connected sequence after year-end.

Section 11 also requires the financial statement to be audited and accompanied by the opinion of a certified auditor, which is why most companies appoint an audit firm alongside their accountant. The only exception in the Act is for Thai registered partnerships below capital, asset or revenue thresholds set by ministerial regulation; limited companies get no size exemption. What goes into the statement, who prepares it and how the annual financial statements are filed with the DBD is its own subject, and the audit itself is a separate engagement with its own timetable.

Tax filings run on their own clocks: the corporate income tax return is due within 150 days of the closing date of the accounting period, and monthly tax filings follow fixed Revenue Department deadlines through the year. Those deadlines belong to the compliance calendar; the point here is that every one of them is prepared from the books the Accounting Act requires.

What keeping books looks like month to month

The Act describes an annual cycle, but a company that touches its books once a year cannot actually comply. The monthly reality looks like this:

1. Documents move. Sales invoices, purchase invoices, receipts, expense claims and bank statements go to the accountant, complete, under Section 12.
2. Entries are made. The accountant records the month in the statutory ledger, in Thai, against those documents.
3. Filings come out. A VAT-registered company files its VAT return (form VAT 30) within 15 days of the following month, every month, even for a nil month. An employer remits social security contributions by the 15th of the following month. Withholding tax remittances run monthly as well.

That documents-in, entries-made, filings-out rhythm is what a bookkeeping engagement actually consists of, and it is why VAT registration changes the tempo of a company's accounting more than any other single event: it converts an annual duty into a hard monthly one.

Keeping it in-house or handing it out

Both are legal. The Act cares that a qualified accountant does the work and that the company supervises them; it does not care whether that accountant is on payroll.

In practice the choice tracks company size. A company with enough volume to occupy a full-time qualified accountant, plus software, supervision and cover for turnover, can bring the function in-house. Most small and mid-sized companies engage an external firm instead, from monthly bookkeeping alone up to a full outsourced accounting back office that also handles the filings and year-end. Fees vary with transaction volume and scope; a firm confirms the current figure for your situation.

Whichever route you take, the duty stays with the company. Choosing a firm well matters precisely because Section 19 leaves the company answerable for its accountant's work. Directories of accounting firms in Thailand exist to make that comparison easier.

What happens when a company keeps no books

The Act's penalty chapter is specific, and it compounds:

• No accounting at all: failing to cause the accounting to be undertaken carries a fine of up to 30,000 baht, plus a daily fine of up to 1,000 baht until the company complies (Section 28). The daily fine means the exposure grows every week the books stay unwritten.
• No annual financial statement: a fine of up to 50,000 baht (Section 30), with a further fine of up to 20,000 baht where the statement is not audited as required (Section 32).
• Sloppy compliance: failing to close accounts on time, to furnish supporting documents or to provide a qualified accountant carries fines of up to 10,000 baht (Section 29); breaches of the retention and language rules carry fines of up to 5,000 baht each (Sections 31 and 35).
• Destruction and falsification: a company that damages, destroys or conceals its accounts faces imprisonment of up to two years or a fine of up to 40,000 baht, or both; false entries or omissions made to distort the true state of affairs carry up to three years or 60,000 baht, or both (Sections 38 and 39).
• Directors personally: where the offender is a juristic person, Section 40 extends liability to the managing director, managing partner or person responsible for its operation, unless that person proves they were not involved and did not consent.

Beyond the Act, a company without books cannot produce a creditable tax return, cannot pass the audit its own annual statement requires, and cannot show a bank, a buyer or an immigration officer a financial position anyone can rely on. The statutory fines are usually the smallest part of the damage.

This guide is general information about Thai accounting law, current as of publication. It is not accounting, tax or legal advice, and the right treatment for a specific company depends on its facts. For decisions about your own books, speak with a qualified accountant or auditor.