Lionel Messi's Argentina are the current world champions
Spain, Portugal and Morocco have been named as the co-hosts, with the opening three matches taking place in Uruguay, Argentina and Paraguay.
The opening matches in South America are to mark the World Cup's centenary as it will be 100 years since the inaugural tournament in Montevideo.
The decision is set to be ratified at a Fifa congress next year.
Fifa also confirmed only bids from countries from the Asian Football Confederation and the Oceania Football Confederation will be considered for the 2034 finals.
Following that decision, Saudi Arabia announced it would be bidding to host the tournament in 2034 for the first time.
Fifa's decision to host the tournament across multiple continents has drawn criticism, with one supporter's body accusing football's world governing body of engaging in a "cycle of destruction against the greatest tournament on Earth".
"[It's] horrendous for supporters, disregards the environment and rolls the red carpet out to a host for 2034 with an appalling human rights record. It's the end of the World Cup as we know it," said Football Supporters Europe.
Fifa president Gianni Infantino said: "In a divided world, Fifa and football are uniting.
"The Fifa Council, representing the entire world of football, unanimously agreed to celebrate the centenary of the Fifa World Cup, whose first edition was played in Uruguay in 1930, in the most appropriate way.
"In 2030, we will have a unique global footprint, three continents - Africa, Europe and South America - six countries - Argentina, Morocco, Paraguay, Portugal, Spain and Uruguay - welcoming and uniting the world while celebrating together the beautiful game, the centenary and the Fifa World Cup."
Montevideo in Uruguay, the city which hosted the first World Cup match in 1930, is poised to stage the opening game in 2030 with matches in Argentina and Paraguay to follow.
The rest of the 48-team tournament will then move to north Africa and Europe.
The change of hemispheres means World Cup teams could find themselves playing in two different seasons at the same tournament.
If the 2030 proposal is approved, Morocco would become only the second African nation to host a World Cup, after South Africa in 2010.
Spain has been named as joint-host weeks after former football federation chief Luis Rubiales resigned following criticism for kissing Jenni Hermoso at the Women's World Cup.
Appearing in court, Rubiales was given a restraining order by a Spanish judge, but denied sexually assaulting Hermoso.
Spain last hosted the World Cup in 1982, with Italy winning the tournament for the third time.
Portugal has never hosted the tournament, but Euro 2004 was held there.
As in previous World Cups, Uruguay, Argentina, Paraguay, Spain, Portugal and Morocco will all qualify automatically as co-hosts.
-- Courtesy of BBC Sport