Visitors can get COVID test for Free in Buenos Aires
 

I visited one of Buenos Aires' free testing sites for COVID, these are run by the Buenos Aires City Government. They confirmed that non resident visitors (of any nationality) are also eligible for the free testing - all that is required is that you are at least 3 years of age and have proof of identification (passport, drivers license, etc.). Test results are sent by WhatsApp and/or email.

Any estimate as to a typical turnaround time for the results?

Antigen tests come back within 3-4 hours of testing. If you get a PCR, those take between 24-36 hours.

This link takes you to a list of testing sites run by the City of Buenos Aires:

lugares de testeo covid gobierno de la ciudad - Bing

For visitors, I think that the Center in La Rural (Palermo) is the best and most conveniently located. Normally tests are drive-thru, but you can also go there on foot or with a Taxi / Uber.

Is it true, that even fully vaccinated foreign tourists visiting Argentina have to take PCR test 5-7 days after arrival in the country? I read it in my local country embassy of Argentina that it is required by ARG laws but here I read couple of posts from people from Argentina that said, that this requirements is cancelled and no other test after arrival is required.
Does anybody have more information about that?

Sounds like a great deal for US residents getting tested for their return flights!

If you are fully vaccinated, you no longer need PCR test 5-7 days after arrival.

Thank you very much. Is there any official source to confirm this? I need for my hiking group so we can establish a plan for the trip and to make everybody sure.

Just look at IATA https://www.iatatravelcentre.com/world.php

Anybody know if these free testing sites are still running? Considering booking a trip for late April and would be interested to know if this might remain an option for testing prior to returning to US. Or is there testing available at EZE?

a friend of mine was there last month and she went to https://www.centralab.com.ar 6500pesos and got the result in 12 hours.

There is a huge testing center at EZE that can do the antigen test (results in 30 minutes or less) or PCR (results in a few hours). To return to US you only need the antigen test. I got my test done there back in December to return home. The line was long but it moved quickly as they had numerous people working. Use the QR code to get the form to fill out as you wait in line, that speeds things along. It isn't free, though. The antigen test costs about $40US, they take most credit cards.

There is also a similar testing facility at AEP, for 4000 pesos each person.