Dual citizen-protocol at Brasil border

[bellasinamor86]

Does anybody know what the protocol is when you have dual citizenship when you enter and leave BA as an American, but want to enter Brasil from AR with a British passport?

I have a friend who is wondering.

 

[sesamosinsal]

Your friend will present the U.S. passport to the Direccion Nacional de Migraciones when she/he leaves Buenos Aires. Upon arriving to Brazil, she/he will present the British passport to the Federal Police of Brazil. If the individual were born in the United States, it would likely say so on the British passport and thus the Federal Police of Brazil may request the U.S. passport -- that's doubtful, though.

The airline will need to see both passports in order to confirm compliance with the Argentine tourist visa (no more than 90 days), as well as immigration regulations (reciprocity) in Brazil.