Income is reported in different categories: A) Salaries, B) Sole Traders, E) Capital, F) Property, G) Capital Gains and H) Pensions and is taxable in Portugal regardless of its origin. For non-residents, only income actually arising in Portugal is subject to assessment.
If you let out furnished accommodations to holidaymakers on a short-term basis, you are engaged in tourist services (Category B) and should have already acquired a Local Lodging licence. This type of business activity receives special treatment under the “Simplified Regime”. You are taxable on only 35% of your invoiced income.