Argentina, Paraguay and Uruguay plan to make a joint bid to host the 2030 World Cup.
The presidents of the three football federations held a joint press conference in Buenos Aires on Wednesday to announce the move.
The bidding process is not due to open for several more years, but Wednesday's announcement coincided with a visit by FIFA president Gianni Infantino to the Argentina Football Association's headquarters.
Argentina and Uruguay signalled their intention to launch a joint bid back in July, with Paraguay's addition strengthening their case.
The 2030 World Cup will be the centenary edition, with Uruguay having hosted the inaugural tournament in 1930.
China reportedly has an interest in bidding to host the 2030 edition, while European nations will once again be eligible under FIFA's rotating system.
Earlier on Wednesday, Infantino had spoken after a visit to the AFA's Buenos Aires office.
"It is an honour and a pleasure to be here, in the home of Argentinian football," he said.
"It is a great emotion to be in a country and in a city that wrote many of the most exciting pages, not only of the history of football, but also its myth. Argentina has contributed to making football what it is today."