2021 FIA Formula 3 Championship

Oscar Piastri left the championship, but will continue to compete for Prema Racing in the Formula 2 Championship.[6][lower-alpha 1] His seat was filled by Formula Regional European runner-up Arthur Leclerc.[7]

Hitech Grand Prix will field all-new lineup as Dennis Hauger left for Prema Racing[8] and Liam Lawson graduated to the team's Formula 2 outfit.[9] The seats were taken by two Red Bull Junior Team members in the person of reigning French F4 champion Ayumu Iwasa and ADAC Formula 4 runner-up Jak Crawford.[10] Roman Staněk will move from Charouz Racing System to join Hitech.[11]

Alex Peroni left Campos Racing to compete in Indy Lights[12] while Alessio Deledda graduated to Formula 2.[13]

Lirim Zendeli and Olli Caldwell left Trident and graduate to Formula 2 with MP Motorsport and move to Prema Racing respectively.[14][15]

Jenzer Motorsport re-signed Calan Williams.[16] Matteo Nannini will switch to HWA Racelab.[17] He will be replaced by Formula Regional European graduate Pierre-Louis Chovet who also raced in two rounds of 2020 season with Hitech Grand Prix.[18]

Red Bull Junior Team member and reigning ADAC Formula 4 champion Jonny Edgar will graduate to the series with Carlin Buzz Racing.[19]

Théo Pourchaire graduated to ART Grand Prix's Formula 2 outfit.[20] The team retained Aleksandr Smolyar and signed Frederik Vesti, who switched from Prema Racing;[21] and Juan Manuel Correa who returns to racing after being seriously injured in a crash in a Formula 2 race in 2019.[22] Sebastián Fernández left the team.

As a consequence of cost-cutting measures, the Formula 2 and Formula 3 championships will adopt a new format. The two championships will alternate between Grands Prix meetings and will no longer appear together on the support race bill. Although this will reduce the number of rounds, both championships will run three races at a Grand Prix instead of two, keeping the overall number of races the same as in previous years. The format change was designed to cut costs for teams competing in both championships by allowing them to rotate staff between each championship.[24]

As the 2020 championship was disrupted by the COVID-19 pandemic, the 2021 calendar will feature substantial revisions:

• The Mugello round and one of the rounds at the Red Bull Ring and Silverstone were removed from the schedule as these rounds were run in support of one-off Grands Prix.
• The Silverstone and Monza rounds that were the part of the British and Italian Grand Prix supporting programmes respectively, were removed from the schedule to make way for the new weekend format.
• The Paul Ricard round will return to the championship.
• The Circuit Zandvoort will make its début in 2021. The circuit had been included on the 2020 calendar, but was removed from the schedule in response to the COVID-19 pandemic.
• The Circuit of the Americas will make its championship début in 2021.

A round at the Bahrain International Circuit had been planned as part of the championship, but was cancelled due to the COVID-19 pandemic. Although the Bahrain Grand Prix was rescheduled, the planned Formula 3 race was abandoned and it was not included on the 2021 calendar.

The weekend format is scheduled to be changed with two races held on Saturday and one race on Sunday. The qualifying will determine the grid of the Sunday race and the first Saturday race, which will also see the top twelve drivers from Qualifying have their grid positions reversed.[25] The grid of the second race will be formed by results of the first Saturday race, with top twelve finishers reversed. The addition of a third race to the weekend will mean that teams are provided with an extra set of tyres.