I didn't buy a return ticket and they didn't ask about one. I just flashed my US passport and Argentinian DNI. Can I stay indefinitely with an Argentinian DNI?
THe DNI allows a 90-day stay in all the neighboring countries, (and most of SouthAmerica), based on reciprocal agreements after Mercosur and later treaties.
I didn't buy a return ticket and they didn't ask about one. I just flashed my US passport and Argentinian DNI. Can I stay indefinitely with an Argentinian DNI?
Are you an Argentine citizen or permanent resident? That's what makes the difference. If the later, yes, I believe so, via a temporary residency permit if you've been a citizen for at least 3-5 years (not sure what Uruguay's requirements are, each country is different for Mercosur naturalized citizens, some don't care, others have time limits before you can apply for a residency permit)
