Korea Plans to Raise the Foreign-Worker Flat Tax to 21%

What exactly did the Ministry propose on 3 August?

Two changes to the flat tax available to foreign employees in Korea. The rate goes from 19% to 21%. The window for electing it, which was due to shut on 31 December 2026, opens again until 31 December 2029.

Both were announced on 3 August 2026 as part of the government’s 2026 tax reform package, and both are proposals. Nothing has changed in your August payroll run. The package amends eleven tax statutes, goes to Cabinet on 1 September and must be submitted to the National Assembly by 3 September, with most measures intended to take effect from 1 January 2027.

The rationale the Ministry gave is worth recording, because it explains why the number moved and why it is unlikely to move back. When the flat regime was introduced, Korea’s top marginal personal rate was 40%. It is now 45%. The gap between what a well-paid Korean employee pays and what a well-paid foreign employee pays had widened by five percentage points without anyone legislating for it, and the increase closes part of that.

How the flat rate works, and what it costs to use

A foreign executive or employee may elect to have their Korean employment income taxed at one flat rate instead of the progressive scale. The election is made either directly to the tax office with the annual return, or through the employer at monthly withholding or at year-end settlement.

The price of that simplicity is total. Elect the flat rate and every income deduction, every exemption and every tax credit is forfeited. Items that would otherwise be non-taxable employment income get added back into the base. There is no partial election and no picking the better of the two after the fact within a single year’s withholding — although the year-end settlement is where the comparison is properly done.

Two features are easy to miss and both matter to a foreign-invested employer.

The first is duration. The flat rate runs for up to 20 years, measured from the first day the employee worked in Korea to the end of the tax year immediately before the twentieth anniversary of that date. It is not a five-year concession, and it is not reset by changing employers within Korea.

The second is the related-party exclusion. The flat rate does not apply where the employee is a related party to the company employing them — a corporation over whose management the employee has direct or indirect controlling influence, or a private company owned by the employee’s relatives. The founder who set up the Korean entity and put themselves on its payroll is frequently outside the regime. That catches people, because the flat rate is widely described as an expat benefit rather than as what it is, which is a targeted incentive with an anti-avoidance boundary.

Does this make the flat rate a worse deal, or a better one?

Both, depending on who you are asking about.

For an employee already on the flat rate, two percentage points of gross employment income is a real pay cut in net terms and nothing is offered in return. On a KRW 300 million package, the incremental national tax is KRW 6 million, plus KRW 600,000 of local income tax on top.

For an employee who has not yet arrived, the extension is worth considerably more than the rate rise costs. Before 3 August, anyone starting work in Korea on 1 January 2027 faced the progressive scale with no flat option at all. If the package passes, they get 21% for up to twenty years. That is a large difference for senior hires, and it removes a deadline that had been quietly distorting start dates — several companies were pulling 2027 arrivals into December 2026 purely to stay inside the window.

The rate rise also moves the point at which the flat election stops being worthwhile. The comparison is always flat rate on gross versus progressive rates on income net of deductions and credits, so the crossover depends entirely on the individual’s household, housing arrangement and deductible spending. What can be said generally is that the crossover moves upward: some employees who are marginally better off on 19% today will be marginally better off on the progressive scale at 21%. Those are the people whose year-end settlement for 2027 needs a genuine comparison rather than a repeat of last year’s election.

What a foreign-invested employer should actually do before January

The useful work in the next four months is modelling and communication, not compliance. Nothing needs to be filed.

Start with a headcount. Identify every foreign employee currently electing the flat rate and every foreign hire whose Korean start date falls in the next eighteen months. For the first group, the question is a net-pay impact of roughly 2.2 percentage points of gross from 2027. For the second group, the question is whether a start date was being engineered around the old 31 December 2026 deadline and can now be relaxed.

Then decide, deliberately, who absorbs the increase. Expatriate packages in Korea are frequently negotiated on a net basis, and a tax-equalised or net-guaranteed package means the employer absorbs the whole two points automatically. A gross package means the employee does. Neither is wrong, but discovering which one you signed up to in February, during year-end settlement, is a bad way to find out. This is exactly the kind of exposure that sits invisibly inside employment contracts until a rate moves, and it is worth reading the clause now rather than budgeting from an assumption.

Then watch the passage of the bill. Rates announced in August are not always the rates enacted in December, and the effective-date wording is where the practical answer for existing electors will be settled.

Where this sits in the wider 2026 package

The flat-rate change is one line in a large document, and it is not the only item in the package that touches foreign-invested companies. The reform also reduces the controlled foreign company low-tax threshold from 17.5% to 15% to align it with the global minimum rate, brings the OECD Pillar Two Side-by-Side Package into Korea’s global minimum tax rules, allows foreign tax credits for qualified domestic minimum top-up taxes, and adjusts the VAT treatment of cross-border services supplied by foreign companies. It also rationalises the separate income tax reduction available to qualifying foreign engineers and researchers.

Groups with a Korean subsidiary inside a Pillar Two perimeter will find more of consequence there than in the flat rate. But the flat rate is the one that appears in an employee’s net pay, which is why it generates the questions.

The government puts the net revenue effect of the whole package at KRW 3.44 trillion on a year-on-year basis, and KRW 13.3 trillion cumulatively from 2027 to 2031. The foreign-worker measure is a rounding error inside that. It was not proposed to raise money; it was proposed to close a fairness gap that had opened up because the top marginal rate moved and the flat rate did not.

If you are working out how the change lands across a specific Korean payroll — particularly where packages are tax-equalised or where employees are near the crossover — that is the sort of question our payroll outsourcing and tax and VAT compliance teams handle as a matter of course. It is also worth reading alongside how Korean severance pay works, since severance is taxed as retirement income on a separate basis and is not affected by the flat-rate election at all.

One honest caveat. If your Korean entity has two foreign employees on modest salaries and no tax-equalisation clauses, this change is a line in a spreadsheet and you do not need help with it. The exposure scales with headcount, with seniority, and with how much of the tax risk your contracts have quietly transferred to the company.

Figures current as at 15 August 2026. The 19% rate and the 31 December 2026 entry deadline are the law in force; the 21% rate and the 31 December 2029 deadline are proposals published by the Ministry of Economy and Finance on 3 August 2026 and are subject to amendment or rejection by the National Assembly. Each figure is linked to the authority it was read from above. This is general information about how Korean rules operate, not advice on any individual’s or company’s tax position.