Portugal belongs to the European Union. There’s a traffic liberalization for people and goods within this space. If you’re coming from a country inside the EU, you might freely circulate. On the other hand, if you’re coming from an abroad country there are some regulations regarding your circulation and good might be apprehended.
At the customs the following documents will be asked for (via airport):
Passport or citizen card (for all travellers)
Passport or citizen card (for minors accompanied by their parents)
Passport or citizen card + special travelling permission (for unaccompanied minors)
Travelers coming from non EU countries should bring the same documentation as EU citizens and a visa might be required.
While passing through the customs there is a list of things you should pay for as well as a list you of products you ought to declare.
Portugal Travel is an organization of Portuguese agencies whose objectives are:
Escola Superior de Hotelaria e Turismo do Estoril
Turismo de Portugal