What Counts as Foreign Income in Thailand — and When Does It Become Taxable?

"Foreign income" is not simply money sitting in a foreign bank account — whether Thailand can tax it depends on three separate questions: where the income was sourced, whether you're a Thai tax resident, and when it was earned versus when it was remitted to Thailand. This article walks through those three questions at a conceptual level. It doesn't replace personalized tax advice for your specific situation.

For the broader 2026 system this fits into — brackets, residency, and filing — see Thailand Personal Income Tax 2026: The Complete Overview.

Which Article Do I Need?

This topic spans several pages on this site, each covering a different part of it:

• Trying to work out whether you're a Thai tax resident? See Am I a Thai Tax Resident? The 180-Day Rule, Explained With Examples.
• Trying to understand the 2024+ remittance rule in detail — what counts as a remittance, capital vs. income, practical timing examples? See Transferring Money to Thailand: 2024 Tax Rules.
• Trying to estimate your actual tax? Use the Annual Tax Calculator.

This page is the conceptual starting point: what foreign income is, what types exist, and at a high level when it becomes a Thai tax question.

What Counts as Foreign Income?

"Foreign-sourced" income means the income itself was generated outside Thailand — as opposed to "Thai-sourced" income, generated from work, assets, or business activity inside Thailand. The distinction matters because it's the first of the three questions above, before residency or remittance timing even come into play.

Employment income needs special care. The employer's country alone does not necessarily determine the source of employment income — where the work is physically performed can matter. Someone who works remotely from Thailand for a foreign employer is not automatically earning "foreign income" just because the paycheck comes from abroad; income for services performed in Thailand can be Thai-sourced even when the employer is not. This is one of the most common misconceptions about foreign income.

Quick Test: Is This Foreign-Sourced Income?

The table below is a practical orientation tool for common situations — not a substitute for applying the full rules to your own facts, and not a database of every possible scenario.

The Three Questions

Once you have a sense of whether income is foreign-sourced, three questions decide whether Thailand can tax it:

1. Where did the income come from? Foreign-sourced or Thai-sourced — the table above is a starting point.
2. Were you a Thai tax resident when it mattered? The foreign-income remittance rules only apply to Thai tax residents. See Am I a Thai Tax Resident?
3. When was it earned, and when was it remitted? The 1 January 2024 dividing line decides which timing rule applies. See Transferring Money to Thailand: 2024 Tax Rules

Why Thai Tax Residency Matters

Foreign income only becomes a Thai tax question at all if you're a Thai tax resident. Under Section 41 of the Thai Revenue Code, a person who stays in Thailand for 180 days or more in a calendar year is treated as a Thai tax resident for that year. Physical presence is the relevant test for this rule — it is not the only thing that can matter for every possible tax question, but it is what determines residency under Section 41, regardless of visa type or nationality.

Non-residents are taxed only on Thai-sourced income, never on foreign income, regardless of remittance. For the full 180-day test, worked day-count examples, and why visa type doesn't decide residency, see Am I a Thai Tax Resident?

What Changed on 1 January 2024

Before 1 January 2024, foreign-sourced income of a Thai tax resident generally became subject to Thai tax only when it was remitted to Thailand in the same calendar year it was earned. Income earned one year and brought into Thailand the following year escaped this rule entirely.

From 1 January 2024, under Por. 161/2566, foreign-sourced income earned by a Thai tax resident on or after that date can be subject to Thai tax when remitted to Thailand — even if the remittance happens in a later year. A clarifying order, Por. 162/2566, confirms that income earned before 1 January 2024 keeps the old same-year-remittance treatment, even if it's remitted in 2024 or later.

In short: the earned date decides which rule applies, and remittance is still what triggers the tax. Whether the current English legal terminology for Por. 161/2566 is best described as an "Order" or a "Circular" varies between sources; this article uses the instrument number rather than guessing at a label.

For what actually counts as a "remittance," how capital is distinguished from income, and worked timing examples, see Transferring Money to Thailand: 2024 Tax Rules — that article covers the mechanics in full; this one only needs the rule itself.

Exceptions Worth Knowing About

A blanket "some exemptions apply" isn't useful on its own, so here are the specific ones this project has verified:

• Qualifying LTR visa holders. The Wealthy Global Citizen, Wealthy Pensioner, and Work-from-Thailand Professional LTR visa categories are exempt from Thai tax on foreign-sourced income that is remitted to Thailand, subject to maintaining the visa's BOI-prescribed qualifications. This is specific to these three LTR categories — it does not extend to other visa types, and it applies to remitted income, not to foreign income regardless of remittance.
• Certain treaty pension provisions. Some pensions are taxable only in the country paying them, under the pension article of the relevant Double Tax Agreement — but this is not uniform. Under the US-Thailand treaty, for example, government and social-security pensions are taxable only in the source country, while ordinary private pensions are taxable only in the country of residence (Thailand, for a Thai resident) — the opposite treatment. Whether a given pension is exempt depends on the pension type and the specific treaty. See How Foreign Pensions Are Taxed in Thailand for country- and pension-type-specific detail.
• Capital, as distinct from income. Money that is capital rather than income was never subject to income tax in the first place — this isn't an exemption, it's a different concept. Savings accumulated before you became a Thai tax resident, for instance, are capital. Whether a specific amount is capital or income can require factual analysis and documentation; the remittance rules article covers this distinction in more depth.

Foreign Tax Credits

Where a Double Tax Agreement between Thailand and the source country applies, foreign tax already paid on the same income may reduce the Thai tax owed on it, subject to that treaty's specific rules and limitations — you generally shouldn't end up paying full tax on the same income twice, though the mechanism and limits vary by treaty rather than working identically for every country. Under the US-Thailand treaty, for example, the credit is capped at the lesser of the foreign tax actually paid and the Thai tax attributable to that same income. That specific formula is a feature of that treaty's text, not a rule that automatically applies the same way under every DTA Thailand has. See Thai Double Tax Treaties: Protecting Expats for how DTAs and foreign tax credits work in general.

If You Answered...

• "I don't know whether I'm a Thai tax resident." → Am I a Thai Tax Resident?
• "I know it's foreign income, but I'm confused about bringing it into Thailand." → Transferring Money to Thailand: 2024 Tax Rules
• "I paid tax overseas and want to know about credits." → Thai Double Tax Treaties: Protecting Expats
• "I want to estimate my actual Thai tax." → Annual Tax Calculator

Worked Example: LTR vs. an Ordinary Visa

Two Thai tax residents each remit foreign pension income. One holds a qualifying LTR Wealthy Pensioner visa and is exempt on that remitted income. The other holds an ordinary long-stay visa (for example, a retirement visa) with no such exemption, and the general residency-and-remittance rules apply. The exemption follows from the specific LTR visa category — not from being a long-term resident or retiree in general, and not from holding any particular non-LTR visa.

Using the Calculator

Once you know which of your income is foreign-sourced and have a sense of whether the rules above apply to it, the Annual Tax Calculator can estimate your Thai tax position. It accepts foreign-income entries with the country, date earned, date remitted, and foreign tax paid, and applies the 2024+ earned-date rule, DTA foreign tax credit logic, and the LTR exemption where applicable, automatically. The calculator computes tax on what you tell it is income — it doesn't determine for you whether a particular transfer is capital or income, and it doesn't resolve treaty pension classification beyond the country/pension-type combinations it already recognizes. Those judgment calls are yours to make first.