The 'Avengers' and 'SNL' stars are in the touristy town of Palermo in Buenos Aires. They were total normies ... sightseeing, holding hands and walking arm in arm. It seemed pretty intimate ... nevermind their bodyguard.
The couple spent Xmas weekend in El Calafate, where they took in the massive Perito Moreno Glacier ... a must-see when visiting the southern part of Argentina.
As we first reported ... Scarlett and Colin started dating back in June 2017 and things really heated up during a romantic dinner a couple weeks later.
Pretty clear this flame's not getting doused anytime soon.