If you have residency in Portugal, you may have to pay tax – even if your income is obtained abroad. However, you can hold a Portuguese residency card without permanently residing in Portugal and may, therefore, not need to pay taxes. You are only considered a resident for tax purposes if you spend at least 183 days out of the year in Portugal. If you spend less than 183 days in Portugal, you will not need to pay tax. However, if you earn any income in Portugal, this will be subject to tax, even if you do not reside in Portugal.