To be technically correct, one would have to refer to the validity of the Portuguese Golden Residency Permit – NOT the Portuguese Golden “Visa”.
As a Golden Visa applicant, you will typically use a regular C-category Schengen Tourist Visa to enter Portugal for your biometrics appointment with SEF.
Thereafter, you will receive a temporary residency permit that is good for two years (24 months). The second temporary residency permit, issued upon renewal, is good for an additional three years (36 months) – that’s a total of five years of temporary residency.
After five years of temporary residency, you can apply for either permanent residency or citizenship, OR you can opt to renew your temporary residency for an additional three years.
In contrast, the Greek Golden Visa is issued with a validity of five years, and is renewable in five-year increments.