Local media estimated that there were already more than 100,000 people waiting for the players at the iconic Obelisk pillar by mid-morning, with more crowds joining from streets on all sides.
The Argentine capital has been in party mode since their dramatic victory over France in Sunday's (December 18) final in Qatar, which gave the country its first World Cup win since Diego Maradona hoisted the trophy 36 years ago.
The players are expected to spend a few hours at the Argentine Football Association facilities near the airport before heading at noon to the huge Obelisk monument in the centre of town.
Argentina beat France 4-2 on penalties after a scintillating 3-3 draw, with Messi scoring twice and France's Kylian Mbappe netting three times.
Messi, 35, said the final would be his last match in the World Cup, though he intends to play a few more games for the national side.
Argentina fans are seen ahead of the victory parade
General view as a Argentina fan kisses a replica trophy ahead of the victory parade
Argentina fans are seen ahead of the victory parade
Fans gather outside of the Association of Argentinian Football Headquarters ahead of the team arrival
Argentina\'s Angel Di Maria, Rodrigo De Paul, Nicolas Otamendi, Paulo Dybala, Cristian Romero, Lisandro Martinez and Lionel Messi are seen on the open top bus as it arrives outside the Association of Argentinian Football Headquarters
Lionel Messi with the trophy during the team\'s arrival at Ezeiza International Airport