When must a company in Thailand register for VAT, and what if it does not?

01Three situations that require registration

Registration comes about in three ways, and only the third is a commercial decision.

• You pass the statutory turnover threshold. A business whose annual turnover exceeds the prescribed threshold must register. The threshold amount is whatever the Revenue Department currently prescribes. Note that this is a compulsory obligation, not a business choice about whether you want to issue tax invoices.
• Certain businesses must register before they start trading. Some types of business are required to complete registration before operations begin.
• Voluntary registration. A business below the threshold may register on its own initiative — because it wants input VAT to be creditable, or because customers require a proper tax invoice. Manufacturers and exporters usually sit here: exports are zero-rated, and only once you are registered does a carried-forward credit or a refund become possible at all. See what actually unblocks an export VAT refund.

For an export factory this one matters especially: with no registration there is no input credit, and the tax paid on purchases is pure cost. Plenty of companies buy equipment and raw materials during the build-out phase before they are registered, and how that input VAT will be treated has to be planned in advance.

02What it costs to have missed registration

It is not a case of quietly catching up:

• The output VAT has to be paid. Sales made during a period when the company should have been registered are still treated as taxable; the output VAT is collected retrospectively, with penalties and surcharge on top.
• The input VAT does not necessarily come back to match it. This is the part that hurts — the output side is certain, while recovering input VAT is subject to conditions on documentation and on the periods involved. One side goes up and the other may not, so in cash terms it is a net outflow.
• Your customers have a problem too. If you cannot issue a compliant tax invoice, your Thai customers cannot claim their input VAT, and that goes straight to the commercial relationship.

03Once registered, the obligations are monthly

Registration puts the company into a monthly filing cycle: output and input VAT are reported every month, and a month with no transactions still requires a nil return. Not filing one counts as late in exactly the same way. This gets overlooked most often during the build-out phase or a slow season — there is little business yet, finance decides there is nothing to report, a few months go by, and cleaning it up afterwards is painful. See the full filing calendar and what falls due when.

Watch the tax month as well. The point at which the liability arises follows defined rules and is not necessarily the point at which you are paid. Invoicing, collection and filing have to line up; otherwise the month in which you report the output VAT and the month in which your customer claims the input VAT will not match, the cross-check will show a discrepancy, and that readily draws a query.

04What registration requires

Broadly: company registration documents, proof of the business premises, identity documents for the legal representative, and material describing the business. The premises have to meet requirements and may be inspected on site. The exact list and procedure follow the Revenue Department's current rules, and local offices can differ slightly in what they ask for.

A practical warning: the registered address and the address you actually operate from must be the same, and must stand up to inspection. This is one of the most common sticking points, particularly for companies using a virtual office address.

05When to have someone else look at it

Three situations where it is worth not deciding on your own: turnover is close to the threshold and you are not sure on what basis it should be counted; the build-out phase has already involved large purchases and you want to know how that input VAT is treated; or you suspect that at some point in the past the company should have been registered and was not. The third especially should be planned as a whole before anything is filed — which periods to correct, in what order, how the surcharge runs. Patching it piecemeal leaves gaps behind.

Whether your company has passed the threshold, when it should have registered, how build-out input VAT is handled and whether there is a historical gap all have to be checked item by item against turnover records, the type of business and the purchase history. What the monthly tax compliance engagement covers.