Hello, Sri,
Assuming you are arriving by air or sea, you need to follow the rules of the Visit Portugal site. I’m assuming you do not have an EU digital COVID certificate. Please note that the CDC card is not considered reciprocal in Portugal and will not be accepted as proof of vaccine, at least as of now. That means that you will need to provide a negative test prior to arrival (PCR within 72 hours of departure, approved antigen 24 hours prior to departure).
https://www.visitportugal.com/en/content/covid-19-measures-implemented-portugal
I’ve cut and pasted the relevant section of the VisitPortugal page:
“Mandatory
- A valid vaccination EU Digital COVID Certificate (with a complete vaccination schedule or with a complete vaccination schedule and a vaccine booster)
- Or a valid test or recovery EU Digital COVID Certificate,
- Or a valid vaccination certificate (with a complete vaccination schedule or a vaccine booster) or recovery certificate issued by a third country, under reciprocal conditions: Albania, Andorra, Armenia, Benin, Cabo Verde, El Salvador, Faroe Islands, Georgia, Israel, Iceland, Jordan, Lebanon, Liechtenstein, Moldova, Monaco, Montenegro, Morocco, New Zealand, North Macedonia, Norway, Panama, San Marino, Serbia, Singapore, Switzerland, Taiwan, Thailand, Tunisia, Togo, Turkey, Ukraine, United Arab Emirates, United Kingdom and the Crown Dependencies (Jersey, Guernsey and the Isle of Man), Uruguay, The Vatican (https://ec.europa.eu/info/live-work-travel-eu/coronavirus-response/safe-covid-19-vaccines-europeans/eu-digital-covid-certificate_en),”