The announcement on Thursday comes two days after Vettel said he and the Italian-based stable would drive their separate ways at the end of the 2020 season.
"Scuderia Ferrari ... is pleased to announce that Carlos Sainz will drive for the team in the 2021 and 2022 seasons of the Formula 1 World Championship," Ferrari said in a statement.
Sainz, 25, who joins from McLaren, said on his Twitter account that he was delighted with the move.
I’m very happy that I will be driving for Scuderia Ferrari in 2021 and I'm excited for my future with the team.
— Carlos Sainz (@Carlossainz55) May 14, 2020
I still have an important year ahead with McLaren Racing and I really look forward to go back racing with them this season. pic.twitter.com/UXkTzFzUgV
Vettel signed for Ferrari in 2015. The four-time world champion had been expected to propel the team to a first drivers' title since 2007.
Mercedes dominant
But the German and Ferrari have been overshadowed by Mercedes who have won six consecutive constructors’ and drivers’ championships.
Vettel, a 32-year-old veteran of 240 Grand Prix, has also been eclipsed by his younger teammate Charles Leclerc.
The 22-year-old gained seven pole positions and won two races during the 2019 season.
The Monaco-born pilot has been unable to underline his supremacy during a 2020 campaign that has been reconfigured due to the coronavirus pandemic.
Sainz, Ferrari bosses believe, will be the ideal foil for Leclerc. He has enjoyed five years of experience on the F1 circuit since making his debut with Toro Ross. The Spaniard moved to Renault in 2017 and two years later switched to McLaren, who have drafted in Daniel Ricciardo from Renault as his replacement.
The moves announced on Thursday leave a vacancy at Renault. Fernando Alonso, who won both his world championships with the team, has been linked with a possible return to the stable.
