If you are a non-resident: You are not taxed on income obtained abroad if you do not live in Portugal. As a non-resident, you only pay tax for income obtained within Portugal, such as from renting out real estate.
If you are a resident: If you are a resident in Portugal, then you have to pay tax on any income obtained abroad.
Taxable income in Portugal is considered:
Employment income.
Pensions.
Director’s fees.
Investment income.
Rental income.
Capital gains.
The tax rate in Portugal is from 14,50% to 48% (for income higher than €80,882). Rental income in Portugal is taxed at a flat rate of 28%.