Argentina
Bolivia and Paraguay border Argentina to the north.
There is sea on the east side of Argentina. Uruguay borders to the north east.
Three countries can be said to border Brazil and Argentina, they are Bolivia, Paraguay and Uruguay.
Uruguay
The country that borders Brazil, Bolivia, and Argentina is Paraguay.
Bolivia.
It IS Uruguay
Argentina is a big country, so it has very long land and sea borders.
Paraguay
Uruguay shares its western border with Argentina.
Uruguay and Northern Argentina