Do I require a visa when travelling to Porto, Portugal?
Nationals of the European Union do not need a visa to enter Portugal. They have the right to reside in national territory for a period up to 90 days without other conditions or formalities beyond holding a valid identity card or passport.
In addition, Visas are not required for example for USA, Canadian, Australian and British nationals. They can stay in the country without a visa for up to 90 days in a 180-day period. Please check here the list of nationalities exempt from holding a visa.
Portugal is part of the Schengen system, which allows visitors to travel to all 29 countries without a visa. Therefore, if travelling from one border-free Schengen country to another, EU nationals are not required to show a passport.
List of countries that are part of the Schengen Area:
Austria, Belgium, Bulgaria, Croatia, Czechia, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Italy, Latvia, Liechtenstein, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, and Switzerland.
List of countries whose nationals need to apply for a visa before travelling to Portugal:
Afghanistan, Algeria, Angola, Armenia, Azerbaijan, Bahrain, Bangladesh, Belarus, Belize, Benin, Bhutan, Bolivia, Botswana, Burkina Faso, Burma/Myanmar, Burundi, Cambodia, Cameroon, Cape Verde Central African Republic, Chad, China, Comoros, Congo, Cote d´Ivoire, Cuba, Democratic Republic of Congo, Djibouti, Dominican Republic, Ecuador, Egypt, Equatorial Guinea, Eritrea, Eswatini, Ethiopia, Fiji,Gabon, Gambia, Ghana, Guinea, Guinea-Bissau, Guyana, Haiti, India, Indonesia, Iran, Iraq, Jamaica, Jordan, Kazakhstan, Kenya, Kuwait, Kyrgyzstan, Laos, Lebanon, Lesotho, Liberia, Libya, Madagascar, Malawi, Maldives, Mali, Mauritania, Mongolia, Morocco, Mozambique, Namibia, Nauru, Nepal, Niger, Nigeria, North Korea, Oman, Pakistan, Papua New Guinea, Philippines, Qatar, Russia, Rwanda, Sao Tome and Principe, Saudi Arabia, Senegal, Sierra Leone, Somalia, South Africa, South Sudan, Sri Lanka, Sudan, Suriname, Syria, Tajikistan, Tanzania, Thailand, Togo, Tunisia, Turkey, Turkmenistan, Uganda, Uzbequistan, Vanuatu, Vietnam, Yemen, Zambia and Zimbabwe.
To enter Portugal, foreigners that are not exempt from it must be holders of a visa which is valid for the duration of the intended purpose of stay. This visa must always be requested at a Portuguese Embassy or Consulate (in Portuguese).
For more information on Portugal visas, please visit the Portugal Ministry of Foreign Affairs website or the Shengen Visa information website.
Important Information: The information available here is for general purpose only. Please contact your nearest embassy for accurate, up-to-date information.
Source: https://www.worldtravelguide.net/guides/europe/portugal/passport-visa/
https://www.worldtravelguide.net/features/feature/a-guide-to-schengen-visas/