The most important things to note about pet travel to Portugal are vaccinations, pet passport, quarantine requirements, and the shipping requirements.
You have to make sure that your pet is fully vaccinated and that the vaccines are up to date. You also have to make sure that your pet has an international pet passport. In addition, you have to take into account all the quarantine requirements that may occur in your country, which depends on the country from which the pet is being shipped or transported. In Portugal, the Department of Veterinary Services issues a procedure that must be complied with that stipulates the exact requirements of importation of any pets including any quarantine requirements.
Also, you have to determine which transportation company you will use, whether it is an airline or a shipping company and whether they have the relevant facilities to house your pets, including in quarantine while they are in transport.
(Cao de agua portugues, the Portuguese water dog, pictured.)