Working with overseas clients as a Thai freelancer: tax, paperwork and getting paid, end to end

Overseas clients usually pay better, pay in a stronger currency, and interfere less. They also come with three questions that trip up a lot of Thai freelancers: is this money taxable in Thailand, what proves the income when there is no withholding certificate, and how do you receive it without losing a slice twice. Here is the whole path, from before you sign to the day you file.

1. Is income from foreign clients taxable in Thailand?

Short answer: if you did the work while physically in Thailand, that income is Thai-source income and belongs on your Thai personal income tax return. It does not matter where the client sits, which bank account received the money, or whether you were paid in dollars, euros or crypto.

The most common mistake is confusing this with the rules on foreign-source income and remittance. Those rules apply when the work itself was performed abroad, or when the income comes from assets located abroad. They do not apply to a freelancer sitting in Bangkok or Chiang Mai sending files overseas. Leaving the balance parked in PayPal does not remove it from the tax base either.

One term worth knowing: staying in Thailand for 180 days or more in a tax year makes you a Thai tax resident. You need that status whenever you want to claim benefits under a double tax agreement.

2. Which income category are you, and what can you deduct?

Your category determines both your deduction rate and your filing obligations.

• Section 40(2) — fees for services you deliver mainly with your own labour and skill: writing, solo design work, consulting. Standard deduction 50%, capped at 100,000 baht when combined with employment income.
• Section 40(6) — the listed liberal professions such as law, accountancy, engineering, architecture and fine arts. 30% (60% for the medical profession).
• Section 40(8) — running a business with real costs, subcontractors or equipment: a studio that hires freelancers, video production, a web team. You can take the prescribed lump-sum rate or deduct actual documented costs.

The practical difference: people with income under Sections 40(5) to 40(8) must file a half-year return in September, while someone with only 40(2) income files once a year. If your work shifts from solo delivery to subcontracting others, your filing calendar shifts too.

3. No withholding certificate — so what proves the income?

A foreign client has no obligation to withhold Thai tax, so you get no 50 ทวิ certificate. The upside is you receive the gross amount. The downside is that you must build the evidence yourself. Keep four pieces per job.

1. The signed contract or the quote the client approved in writing, including the confirming email.
2. The invoice you issued, with a continuous number series and no gaps.
3. Proof of receipt: the bank statement line, or the transaction report from Wise, Payoneer or PayPal, including fees deducted.
4. A note of the exchange rate used on the day the money actually arrived.

File them together per invoice, not in four folders sorted by document type. When someone asks questions later, the question is always "where did this deposit come from", never "how many invoices did you issue".

4. Foreign withholding and double tax agreements

Some countries require the payer to withhold tax on payments leaving the country, especially when your fee is classified as a royalty rather than a service fee. Thailand has double tax agreements with more than 60 countries, which may reduce that rate or assign taxing rights to Thailand alone.

What to do:

• Ask before signing whether tax will be withheld at source, and at what rate.
• If tax is withheld, get the foreign withholding certificate. It is the document you need to claim a foreign tax credit on your Thai return.
• To claim treaty benefits you must evidence Thai tax residency; the Revenue Department issues a residence certificate for this.
• US clients will usually ask for a W-8BEN confirming you are not a US taxpayer. This is routine. Fill it in exactly as it appears on your passport and your real address.
• Put a clause in the contract stating the agreed price is the net amount the contractor must receive, and that any withholding in the client's country is borne by the client. This one sentence saves more money than most people expect.

5. VAT: zero-rated is not the same as VAT-free

Services performed in Thailand and used entirely abroad qualify as exported services, taxed at 0% VAT. Two traps follow.

• Zero-rated revenue still counts toward the 1.8 million baht annual registration threshold. A freelancer working exclusively for overseas clients who crosses it must still register.
• If the service is used in Thailand, it is 7% even when the client is a foreign company — an event held in Thailand, photography of a Thai launch, marketing aimed at Thai consumers for an overseas brand.

Some freelancers below the threshold register voluntarily to reclaim input VAT on equipment and software, accepting monthly PP30 filings in return. Decide that on your actual annual input VAT, not on how professional registration feels.

6. Getting paid without losing money twice

International transfers always carry two costs: the visible fee, and the invisible exchange rate margin. The second is usually the bigger one.

• Bank wire (SWIFT) suits large amounts and corporate clients. Agree in writing who pays the charges — the OUR instruction means the sender covers all of them. Otherwise the amount that lands is smaller than the amount you invoiced.
• Wise or Payoneer typically give better rates and give your client local receiving details in their own country, which removes friction on their side.
• A foreign currency deposit account is worth it if you already have dollar expenses and want to stop converting back and forth.
• Large inbound transfers come with a purpose declaration required under Bank of Thailand rules. Answer accurately — it is a service fee — and keep the invoice ready.
• Never receive client money into the account you spend from personally. A separate receiving account turns year-end reconciliation from a day into an hour.

On recording: individuals are taxed on a cash basis, so income arises on the day you actually receive it. Convert at that day's rate, and record both the gross amount and the fees deducted. Do not record only the net that landed — those fees are deductible if you claim actual expenses.

7. What an English-language invoice must contain

Overseas clients pay late because of incomplete paperwork far more often than out of unwillingness. To clear their accounts payable on the first pass, include:

• Invoice number, issue date, and a due date written as a real date, not just "Net 30".
• Your legal name and address plus your 13-digit Thai tax ID.
• The client's legal entity name and address exactly as they gave it, with their VAT or EIN if they ask for it.
• A description of the work that a person outside the project can understand.
• The currency spelled out — USD, not just a dollar sign.
• Full bank details: account name, account number, bank name, branch address, SWIFT code.
• Who bears the transfer charges, and your late payment terms.

8. The things people forget until they hurt

• Currency risk. On multi-month engagements, convert in stages as each payment arrives instead of waiting for the perfect rate, and price in some volatility on long contracts.
• Reserve tax on every deposit. Nobody is withholding 3% on your behalf the way Thai clients do. Move 15–20% of each incoming payment into a tax account the same day, or March becomes brutal.
• Social security and health cover. Working for foreign clients means no employer in the system. Consider Section 40 registration and your own health insurance.
• Proving income for a loan. Banks read 6–12 months of statements alongside your tax filings. If income is scattered across channels and never fully declared, a mortgage gets much harder. This is the most underestimated cost of staying off the books.

Checklist before your first overseas job

1. Agree currency, transfer method and who pays fees, in writing.
2. Ask about withholding at source and add the net-of-tax clause.
3. Open a separate account for client payments.
4. Run one continuous invoice number series for the year.
5. Set a standing rule: 15–20% of every payment goes to the tax reserve.
6. Keep contract, invoice, statement line and FX rate together per job.
7. Track your rolling annual revenue against the 1.8 million baht VAT threshold.
8. If you have business-type income, put the September half-year filing in your calendar.

If you want that whole set in one place, MANA issues bilingual quotations and invoices, links each document to a project and a contact, and matches incoming payments to specific invoices — so when evidence is requested months later, you find it by the job rather than by digging through files.