Side Income in Korea: The Permission You Need First, and 3.3% vs 8.8%

If you are living in Korea and thinking about picking up freelance work, tutoring, or an online side project, there are two separate questions to answer, and most guides only answer the second one.

The first is whether you are allowed to do the work at all. The second is what happens to the money. Koreans only have to think about the second. You have to clear the first one too, and the penalty for getting it wrong is not a tax bill.

A foreign resident working on a laptop at a window seat in a Seoul cafe

The gate before the tax: permission to work outside your status

Korean immigration law ties what you may do to the visa you hold. Article 18(1) of the Immigration Control Act limits employment to the status you were granted, and Article 20 requires the Minister of Justice's permission before you engage in activities outside it. In practice this is the 체류자격 외 활동허가 — permission for activities outside your status of stay.

This is not a formality. Working without it carries up to three years' imprisonment or a fine of up to 30 million won, and it can end in deportation. A side gig that pays 400,000 won a month is not worth that.

The rule catches more people than you would think. A D-2 student doing paid tutoring, an E-2 teacher taking outside classes, an E-7 professional doing weekend freelance work — all of these are activities outside the granted status, and all of them need permission first.

Where to sort it out: the permission is granted by an immigration office, and the Immigration Contact Center on 1345 answers in multiple languages — weekdays 09:00 to 22:00, with Korean, English and Chinese after 18:00. Ask before you take the work, not after. Permission is granted going forward; it does not repair work already done.

If you are on a student visa, there are hour limits too

Students get a defined allowance rather than an open door, and the ceiling moves with your Korean proficiency and how far along you are.

Status	Term-time hours per week
Undergraduate, years 1–2	10 hours; up to 25 with higher Korean proficiency
Undergraduate, years 3–4	10–15 hours; up to 30 with higher proficiency
Graduate students	15–30 hours; up to 35 with higher proficiency

Vacation periods are generally unrestricted for undergraduates. Because the bands depend on your TOPIK level and your year, the office that grants the permission is the one that decides your number — do not assume a figure you read in a forum applies to you.

Now the money: 3.3% or 8.8%

Once you are cleared to work, Korean tax law treats your income exactly as it treats a Korean resident's. Whoever pays you withholds tax before the money lands. The percentage tells you how your income was classified.

Withheld	Classified as	Typical case
3.3%	Business income (사업소득)	Ongoing, repeated work — a freelance contract, regular outsourced work, a shop
8.8%	Other income (기타소득)	One-off work — a single lecture, a manuscript fee, an occasional consultation

The rates come from Article 129(1) of the Income Tax Act: item 3 sets withholding on business income at 3 per cent, item 6(d) sets most other income at 20 per cent. Local income tax adds another 10 per cent of that, which is where the 3.3 comes from.

Why other income shows up as 8.8 and not 22

Because the 20 per cent is not applied to what you were paid. It is applied to other income after expenses, and Article 87 of the Enforcement Decree lets a defined set of categories deduct 60 per cent as deemed expenses without producing a single receipt.

Step	On a 1,000,000 won fee
Gross payment	1,000,000 won
Deemed expenses, 60%	− 600,000 won
Taxable other income	400,000 won
Income tax at 20%	80,000 won
Local income tax	8,000 won
Withheld	88,000 won — 8.8% of the gross

So the lower number is not a lower rate. It is the same 20 per cent applied to a much smaller base.

The dividing line is one word: "temporarily"

Article 21(1)19 of the Income Tax Act defines the relevant category of other income as consideration for personal services provided temporarily — lecturing without an employment relationship, work by someone with specialist knowledge or a particular skill, and other services performed for a fee outside employment. Item 15 covers manuscript fees, royalties, and payment for original creative work in art, music, and photography.

What decides it is not the amount. It is whether the work is occasional or continuous and repeated. The same lecture is other income once and business income every month. And you do not make the call — the payer classifies it when they withhold, and that record goes to the National Tax Service.

People of different nationalities waiting in a bright public office waiting area in Korea

One thing Koreans never have to check: are you a resident for tax?

Everything above assumes you are a resident in the tax sense, which is not the same as holding a residence card. Article 1-2(1)1 of the Income Tax Act defines a resident as an individual who has an address in Korea or a place of abode here for 183 days or more. Anyone else is a non-resident.

The distinction decides how much of your income Korea taxes. A resident is taxed on worldwide income; a non-resident is taxed on Korean-source income only. If you arrived partway through the year and your side work started early, it is worth knowing which side of 183 days you fall on before you assume the rules above apply to you unchanged.

Two practical points follow. Your foreign registration number is what the payer uses to report the withholding, so the income is traceable to you from the first payment. And the withholding itself happens the same way regardless — the classification question of 3.3 versus 8.8 does not change with nationality.

Under 125,000 won a payment, there is no tax at all

Article 84(3) says other income is not taxed when the taxable amount is 50,000 won or less per payment. With the 60 per cent deduction applied, that works out to a gross payment of 125,000 won.

The wording matters: it is per payment, not per year. Several small jobs are each measured on their own.

The 3 million won threshold is really 7.5 million

Article 14(3)8(a) keeps other income out of your annual return when the taxable other income is 3 million won or less and it was withheld at source. This is called separately taxed other income.

Again the figure is measured after the deduction. Where the 60 per cent applies, 3 million won of taxable income corresponds to 7.5 million won actually received. People who remember only "3 million" routinely underestimate their own headroom by more than half.

The same provision lets you opt out: if you would rather fold the income into your annual return, you can, and in a low-income year that can bring back some of the 8.8 per cent already withheld.

Business income has no such threshold

This is the part that catches people. Everything above is a rule about other income. Article 14(3) does not offer separate taxation for business income at all.

Article 73(1) lists who may skip the May final return. Someone with employment income only may skip it. Someone with employment income plus separately taxed other income may skip it. Someone with employment income plus business income is not on the list — so if any of your side work was withheld at 3.3%, you file in May, whatever the amount.

What you have	May final return
Salary only	Not required
Salary + other income, 3m won or less taxable	Not required
Salary + other income above that	Required
Salary + any business income (3.3%)	Required, any amount

Filing is usually in your favour. Business income lets you claim real expenses, and many people get back a good part of the 3.3 per cent that was withheld. The cost falls on those who simply do not file, because penalties attach to that.

One more line that catches foreign employees out: the 3.3% and 8.8% figures above are withholding on side income, not your final tax. How your main salary is taxed is a separate election, and taking the flat rate there switches off every deduction — Korea's Flat Tax for Foreign Workers 2026: 19% Now, 21% Proposed From 2027.

The short version

Check your visa first. Activities outside your status need permission under Articles 18(1) and 20 of the Immigration Control Act; working without it risks up to three years' imprisonment or a 30 million won fine, and deportation.
Students have weekly hour caps that depend on year of study and Korean proficiency.
3.3% means business income. 8.8% means other income. The test is whether the work is temporary.
8.8% looks small because 60 per cent of the payment is deducted as deemed expenses first.
No tax at all on other income of 125,000 won or less per payment.
The separate-taxation ceiling is 3 million won of taxable other income — about 7.5 million won received.
Any business income at all means you file in May, regardless of size.
Check whether you are a tax resident — an address in Korea or 183 days of abode. It changes what Korea taxes.