Under-declaring foreign income abroad? How expats might be unknowingly exposed

For many South Africans living and working overseas, tax compliance is often treated as an afterthought. But when it comes to expat tax in South Africa, what you don’t know can cost you far more than you expect.

A common and dangerous misconception is that earning income abroad automatically removes your obligation to declare it in South Africa. Your tax liability depends on your tax resident status, not your physical location. If you haven’t yet formally ceased residency, you may still be fully exposed to tax on foreign income in South Africa.

With the South African Revenue Service (SARS) increasingly relying on global data-sharing agreements and advanced analytics, under-declaring income — even unintentionally — is becoming easier to detect and far more costly to ignore.

Top 3 takeaways for expats on foreign income tax in South Africa:

1. Your tax residency matters more than where you live. If you haven’t formally changed your tax resident status, you are still liable for South African tax on foreign income.
2. Under-declaring income carries serious consequences. The revenue authority can impose SARS understatement penalties of up to 150%, plus interest, along with possible criminal charges.
3. SARS already has global visibility. Through international reporting systems, SARS can detect discrepancies between declared income and actual earnings abroad.

Read more: Reality check: Leaving South Africa doesn’t always mean leaving SARS behind.

The expat trap: misunderstanding tax residency in South Africa

SARS operates a residency-based tax system. This means your obligations under personal tax in South Africa depend on whether you are classified as a tax resident or a non-tax resident of South Africa.

If you are still considered a tax resident, you must declare and pay expat tax on your worldwide income, including:

• Foreign employment income
• Consulting or freelance earnings
• Offshore investments and dividends
• Rental income from foreign property
• Capital gains from global assets (subject to capital gains tax in South Africa)

Many expats fall into the trap of assuming that relocating or working abroad automatically exempts them from tax on income in South Africa. Others incorrectly believe that declaring only South African-sourced income is sufficient. This is where problems begin. If your South African expat tax profile shows limited or no foreign income while external data suggests otherwise, SARS may flag your return for review.

Read more: Dangerous misconceptions about financial and tax emigration from South Africa.

How under-declaring income happens (often unintentionally)

In many cases, under-declaration is not deliberate. It often stems from confusion or misinformation around tax for expats in South Africa.

Common scenarios include:

• Declaring only local bank interest or rental income while ignoring foreign earnings
• Submitting “nil returns” despite earning income abroad
• Misunderstanding the foreign employment income exemption thresholds
• Failing to update tax residency status after relocation

Even if these errors are unintentional, they may still be classified by SARS as under-declared income tax, which can trigger penalties under the South African Income Tax Act and the Tax Administration Act.

Read more: How South African expats can safeguard their foreign employment income abroad.

SARS penalties – the real cost of non-compliance as an expat

Under-declaring income is not a minor administrative issue. It can escalate quickly into a significant financial and legal burden.

SARS may impose:

• Understatement penalties ranging from 10% to 150%
• Interest on unpaid taxes, compounding over time
• Retrospective audits and reassessments
• Criminal charges in severe cases

The severity of the penalty depends on behaviour. Under Section 223 of the Tax Administration Act, SARS evaluates whether the understatement resulted from:

• A bona fide error
• Negligence
• Gross negligence
• Intentional tax evasion

A substantial understatement — where the tax shortfall exceeds a defined threshold — can result in a substantial tax understatement penalty, even if there was no intent to evade tax. For provisional taxpayers, additional exposure exists through the SARS provisional tax understatement penalty, which applies when income estimates are significantly understated.

Why expats are at higher risk of under-declaring personal income

For expats, the risks linked to foreign income tax in South Africa are often more complex than expected.

1. Misaligned tax status: Many individuals assume they are non-resident taxpayers in South Africa simply because they live abroad. Without formally ceasing tax residency, this assumption is incorrect.
2. Partial disclosure: Declaring only additional income in South Africa while omitting foreign earnings creates inconsistencies that are easy for SARS to detect.
3. False sense of distance: Being geographically distant from South Africa does not reduce your obligations under tax on foreign income in South Africa.
4. Increasing enforcement: SARS is actively targeting non-compliance among expats, particularly those earning above exemption thresholds.

Read more: Hot question: Do you pay tax in South Africa if you live abroad?

The global reach of SARS: why hiding income no longer works

SARS has significantly expanded its ability to track offshore income. Through international agreements such as the Common Reporting Standard (CRS), SARS receives data from:

• Foreign banks and financial institutions
• Investment platforms
• Tax authorities in other jurisdictions

This information is cross-referenced against your South African tax return. If discrepancies are identified, SARS can initiate audits or issue revised assessments. In addition, SARS uses advanced data analytics and machine learning to identify patterns of substantial understatement of income. Dedicated units monitor expats and verify whether declared income aligns with global financial data.

Long story short? SARS knows more about your financial position than you think.

Read more: Warning – SARS is monitoring South African expats abroad who want to return home.

The role of tax residency: where everything comes together

Your tax residency status in South Africa is the single most important factor in determining your expat tax exposure.

If you have not formally ceased residency:

• You remain liable for South African tax on foreign income
• You must comply fully with personal tax in South Africa
• You are at risk of penalties for any under-declaration

However, ceasing tax residency is not automatic. It requires a formal process with SARS, known as tax emigration. Once SARS has approved your tax residency status change, you become a non-resident for tax purposes, and your tax obligations shift. You are then generally taxed only on South African-sourced income, reducing your exposure to global income reporting requirements.

Read more: South African tax residency rules – expats, are you still tax residents of South Africa?

Compliance is no longer optional.

The regulatory environment has changed. SARS has both the tools and the mandate to enforce compliance aggressively.

Under the South African Income Tax Act and the Tax Administration Act, failure to declare income accurately is treated seriously, regardless of intent. The inclusion of criminal sanctions highlights the importance of full and timely disclosure.
For expats, this means that even small omissions can escalate into larger issues over time — especially when combined with interest and penalties under income tax act provisions.

FinGlobal: expat tax compliance specialists for South Africans

If you are living abroad and unsure about your tax position, act now — before SARS does. Review your tax residency status, make sure your income is fully declared, and fix any compliance gaps while you still can. The risks of getting it wrong are high, but they are also avoidable. With the right support, you can resolve issues early and move forward with confidence.

FinGlobal can help you every step of the way, from tax emigration and expat tax compliance to retirement annuity encashment — so you can protect your financial freedom and stay on the right side of SARS.

Ready to find out how we can streamline your tax affairs and lighten your cross-border stresses? Leave your contact details below, and we’ll be in touch to discuss your needs.