Renault issued a short statement saying discussions with Ricciardo over a renewal of his contract had not been successful.
Vettel will be replaced by McLaren’s Carlos Sainz, with Ferrari keen to employ a second driver to play a supporting role to Charles Leclerc, the 22-year-old who won two races last season and established himself as Ferrari’s best chance to unseat Mercedes and Lewis Hamilton at the top of the sport.
Leclerc signed a contract extension until the end of the 2024 campaign in the off-season.
Sainz’s departure, after McLaren relinquished an option it had on his services for 2021, allowed Ricciardo to pair with young Briton Lando Norris, with both drivers set to receive equal equipment and opportunity as McLaren looks to rejoin the fight at the front of the field with Mercedes, Ferrari and Red Bull Racing.
“Daniel is a proven race-winner and his experience, commitment and energy will be a valuable addition to McLaren and our mission to return to the front of the field,” McLaren team principal Andreas Seidl said in a statement.
“With Daniel and Lando as teammates, I believe we have two racers who will continue to excite our fans and help the team grow.”
Ricciardo had numerous discussions with McLaren about a move for the 2019 season before electing to sign with Renault for two years. Both McLaren and Renault used Renault engines last year, with McLaren emerging on top to finish fourth in the constructors’ championship, and scoring its first podium finish in six years with Sainz third in Brazil.
McLaren will switch to Mercedes engines, which have won all six world championships since the sport moved to turbo hybrid engines in 2014, from the 2021 season onwards.
In 171 grand prix starts, Ricciardo has won seven races, all for Red Bull Racing between 2014-18, and has twice finished third in the world championship.
Fernando Alonso, who won world titles for Renault in 2005-06, has been flagged as a potential replacement for Ricciardo. Alonso, 38, retired from F1 in 2018 after winning 32 races with Renault, McLaren and Ferrari.