Tax is the expat topic that causes the most confusion and the most expensive mistakes. This guide explains the core ideas every expat needs: how countries tax their residents, what a territorial system actually means, and why your home country’s tax does not vanish the moment you board the plane.

The Two Global Tax Systems

Worldwide taxation

Most major economies tax their residents on all income, wherever it was earned. France, Germany, Australia, Canada and most of the OECD work this way. The logic is simple: if you live here, you owe tax here — on everything.

The United States goes further. It is one of only two countries in the world (the other is Eritrea) that taxes its citizens on worldwide income no matter where they live. An American in Nicaragua, Thailand or Paraguay still files a US return every year. Living abroad changes the complexity, not the obligation.

Territorial taxation

A territorial system taxes only income that comes from inside the country’s borders. If your income comes from outside, it falls outside the local tax net entirely. This is what makes Nicaragua, Georgia, Panama, Paraguay, Malaysia and Thailand attractive to expats.

A US retiree living in Nicaragua, drawing Social Security and income from a US brokerage account, owes zero Nicaraguan income tax on that income. Legally. By design. Territorial systems are not tax evasion — they are a deliberate policy choice by countries that want foreign residents and their spending, but make no claim on income earned elsewhere.

For US citizens, worldwide taxation applies regardless. For Canadians and Britons, the rules are based on facts and circumstances — leaving the country does not automatically end home-country tax residency. The two systems run in parallel. Understanding both, and how they interact, is the job of a dual-jurisdiction specialist — not a general accountant.

What Expats Actually Pay

• Local country: taxes only income sourced within that country. Foreign pension, foreign investment income, foreign salary — zero local tax.
• Home country (non-US): depends on whether you have successfully severed home-country tax residency. If yes, zero. If no, home-country rates still apply.
• Home country (US): US citizens always file. What you owe depends on income type, the Foreign Earned Income Exclusion, Foreign Tax Credits and treaties. For most retirees the net liability after exclusions and credits is manageable — but filing is still required.

Local income — when you do owe local tax

Territorial systems only exempt foreign-source income. Rent out a property in Nicaragua and that rental income is Nicaragua-sourced — taxed in Nicaragua at local rates. Run a business in Georgia serving Georgian clients and that income is Georgia-sourced. Foreign income is exempt; local income is taxed normally.

Home Country Obligations by Nationality

US citizens

The IRS follows US citizens everywhere. Key obligations:

• Annual return (Form 1040): required regardless of income or location. Filing thresholds abroad are very low (around $12,550 single; $400 for self-employment — verify current figures).
• FBAR (FinCEN 114): required if foreign financial accounts exceed $10,000 in total at any point in the year.
• FATCA (Form 8938): required for higher-value foreign assets — thresholds from $50,000 to $600,000 depending on status and residence.
• Foreign Earned Income Exclusion (Form 2555): excludes a large amount of foreign earned income — salary and self-employment, not passive income like pensions or dividends.
• Foreign Tax Credit (Form 1116): credit for foreign income taxes paid. Less valuable in low-tax territorial countries — the FEIE is usually better for earned income.
• PFIC rules: foreign mutual funds and ETFs face punishing treatment. Structure your portfolio carefully before you go.

Canadian citizens

Canadian tax residency is not triggered by a passport or visa — it is based on residential ties. Keeping a home, bank accounts, provincial health cover, a licence or family in Canada may keep you a tax resident even if you live abroad permanently. The CRA uses a facts-and-circumstances test, and a departure tax may apply on certain assets. Speak to a cross-border advisor — ideally 12 months before you leave.

UK citizens

The UK Statutory Residence Test (SRT) weighs UK days, “ties” (home, work, family, prior residence) and the nature of your departure. There are three tests — automatic overseas, automatic UK, and sufficient ties. “Split year treatment” can split the year of departure but does not remove that year’s obligations. You need a specialist who knows the SRT cold.

Australians

Australia uses a domicile-based test. Like Canada, simply leaving does not break residency if you intend to return or keep ties. The ATO scrutinises returning expats — get advice before and after departure.

Double Tax Treaties

Many countries sign Double Taxation Agreements (DTAs) that decide which country has primary taxing rights over each income type — employment, pensions, dividends, capital gains. The US–Georgia treaty, for example, affects how US citizens in Georgia are taxed on specific income; Nicaragua has a limited treaty network. Treaties do not remove obligations — they decide which obligation takes priority and stop you being taxed twice on the same income.

The Dual-Jurisdiction Specialist

The single most important professional decision an expat makes is finding a tax advisor who understands both the local system and their home country’s system. A Nicaraguan accountant knows Nicaraguan law; a Georgian accountant knows Georgian law; neither necessarily understands US worldwide taxation, Canadian departure tax or the UK SRT. You need someone who knows both sides — and that is rarely the general accountant you’ve used for 20 years.

At Expat Connect Services we connect expats with dual-jurisdiction professionals who understand the cross-border picture — what Nicaragua or Georgia can tax you on, and how it interacts with your home obligations.