It is the first time the 27-year-old has played for a club outside of Portuguese football and it brings his three-year spell with Braga to an end.
The 6' 3" striker has played 18 times for his country, scoring his only international goal in the recent 1-0 friendly win over Italy.
Porto sign in-demand French midfielder Giannelli Imbula
The centre-forward is Swansea's fourth signing of the summer, joining Ghana forward Andre Ayew, French left-back Franck Tabanou and Swedish goalkeeper Kristoffer Nordfeldt to the club.
He has signed a three-year deal at the Liberty Stadium and will compete with French striker Bafetimbi Gomis for a place in the Swansea attack.
Atletico Madrid trigger Jackson Martinez's Porto release clause
Swansea on verge of signing Franck Tabanou