Before you start

An ARC (Alien Resident Certificate) or, for short stays, a passport/visa — your day-count and entry/exit records drive your residency status
Track your physical days in Taiwan precisely: 183+ days in the Jan 1-Dec 31 calendar year flips you from non-resident to resident
If employed locally, a Taiwan employer who withholds tax and issues a year-end withholding statement (扣繳憑單); if paid from abroad, records of income source and where the work was performed

Step-by-step

1
Determine your residency status for the tax year
Count your physical days of presence in Taiwan across the calendar year (Jan 1-Dec 31). 183+ days = tax resident (progressive 5%-40%, deductions and exemptions apply). 1-182 days = non-resident. Non-residents staying 91-182 days have Taiwan-source salary withheld at a flat ~18% with no deductions; those staying ≤90 days are also taxed at 18% on Taiwan-employer salary (income from a foreign employer for ≤90-day stays is generally not taxed). Residency is assessed per calendar year, so your status can differ from one year to the next.
OnlineWho: You (self-assessment); confirm with the National Taxation Bureau of Taipei if borderlineOngoing through the year; settled at year-endFree
2
Have tax withheld during the year (or set aside for self-payment)
If a Taiwan entity pays you, it withholds at source: non-residents at the flat ~18% on each salary payment, residents at a lower withholding rate (often 5% or per the withholding tables). The brutal first-year trap: if you arrive mid-year, your employer must withhold at the non-resident ~18% rate until you actually reach 183 days of presence — so early paychecks are docked at 18% even though you'll end up a resident. You reclaim the excess at filing. Remote workers paid from abroad have no Taiwan withholding and self-report any Taiwan-source portion at filing.
Via employerWho: Your Taiwan employer/payer (withholding agent); you if self-employed or paid abroadEach pay cycle throughout the year~18% non-resident / lower resident withholding on Taiwan-source salary
3
File your annual income tax return in May
Residents file between May 1 and May 31 for the prior calendar year (the deadline is sometimes extended — verify each year). File online via the eTax portal (tax.nat.gov.tw), logging in with your NHI card + PIN, a Citizen Digital Certificate, or your ARC-based credentials; the system pre-fills your withholding data. Residents apply the personal exemption (~NT$97,000), the standard deduction (NT$131,000 single / NT$262,000 married filing jointly for the 2025 year) and the special salary deduction. Foreign-source income is normally excluded from this return but may trigger a separate AMT computation.
OnlineWho: You; the National Taxation Bureau of Taipei processes itMay 1-31 (file the prior calendar year)Free to file online
4
Settle the balance or claim your refund
Pay any tax due by the filing deadline (online banking, convenience store, ATM, or credit card) or, if you over-withheld — very common for first-year residents hit with 18% early-year withholding — receive a refund. Refunds for May filings are typically paid by direct deposit in tranches later that year. Keep your withholding statements and proof of days present in case the Bureau queries your residency.
OnlineWho: You; National Taxation Bureau of Taipei issues refundsPayment due May 31; refunds paid out over the following monthsTax owed, or NT$0 / refund if over-withheld

Documents you’ll need

ARC (Alien Resident Certificate) or passport with entry/exit stamps (proof of days present)
Year-end withholding statement(s) from your employer (扣繳憑單)
NHI card + PIN, Citizen Digital Certificate, or ARC login credentials for eTax
Taiwan bank account details (for refund deposit)
Records of foreign-source income and where work was performed (relevant for AMT and source determination)
Gold Card and prior-residence evidence, if claiming the Gold Card tax incentive

Things most newcomers don’t know

First-year arrivals get hammered at the 18% non-resident rate until they physically cross 183 days — but they reclaim the excess at filing once they qualify as residents.

Withholding agents must apply the non-resident ~18% rate while you are still under 183 days of presence, because residency is only confirmed at year-end. New arrivals often think they're being overtaxed; in fact the over-withholding is refunded after the May return, so budget for the cash-flow gap rather than a permanent loss.

Source: National Taxation Bureau of Taipei (ntbt.gov.tw)

Foreign-source income is generally outside Taiwan's regular income tax — it only appears in the 20% Alternative Minimum Tax, which carries a ~NT$7.5M basic-income exemption.

Taiwan's territorial system means income tied to an overseas source typically isn't taxed under the ordinary income tax. It instead feeds the AMT (Income Basic Tax), but only foreign income above NT$1M counts and tax applies only on basic income above NT$7.5M — so most remote workers paid from abroad pay little or nothing. The 'source' rules are nuanced (where you perform the work matters), so get advice before assuming income is exempt.

Source: Ministry of Finance — AMT / Income Basic Tax

Qualified Gold Card professionals get half of salary income above NT$3M excluded from tax for up to 5 years — plus an exclusion of overseas income from the AMT in those years.

For five tax years from the first qualifying year, 50% of salary above NT$3M is excluded from assessment, and qualifying overseas income is left out of the AMT calculation. On a NT$8.2M salary this can exclude roughly NT$2.5M from tax — a large saving high earners frequently miss because they never formally apply.

Source: goldcard.nat.gov.tw / mof.gov.tw tax incentive

Common mistakes to avoid

Miscounting days: 182 vs 183 is the line between flat 18% with no deductions and the full resident regime — count entry/exit days carefully, as residency is strictly per calendar year and doesn't roll over
Assuming the 18% early-year withholding is permanent and not filing — you forfeit a refund you're owed if you skip the May return
Treating all 'remote' income as automatically tax-free: income for work physically performed in Taiwan can be Taiwan-source even if paid by a foreign company, and AMT can apply to large foreign-source amounts
Forgetting US citizens and green-card holders still owe US tax on worldwide income — use the FEIE and/or Foreign Tax Credit; the US has no tax treaty with Taiwan
Leaving Taiwan mid-year without settling tax — departing non-residents may need to clear tax before exit rather than waiting for May
Not applying for the Gold Card tax incentive: it must be claimed with the proper Gold Card/work permit in place — it isn't automatic