When does a foreigner in Korea still need a global income tax return after payroll?

Question

I worked in South Korea and some tax was already settled through employment processes. Please explain when a foreigner may still need to file a global income tax return, why side income matters, and why May filing season is still important.

TaxGuided · Accepted Answer

Foreign employees in Korea often assume the payroll year-end settlement closed the book for good. Sometimes it did. Sometimes it absolutely did not. The NTS filing materials still reserve a distinct May filing season for global income tax, and KOTRA's Taxation in Korea guide explains that business income requires filing and that financial income above certain thresholds can also push a taxpayer into the global return.

That is the moment where side income stops being a side note. Freelance recei

When does a foreigner in Korea still need a global income tax return after payroll?

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