Ex-Williams F1 junior to become latest Formula E convert
Zak O’Sullivan will become the latest junior single-seater racer to switch to Formula E after agreeing to become Maximilian Guenther’s team-mate in an all-new Envision team line-up.
Current Super Formula and Super GT driver O'Sullivan is set to end his two-year stint in Japan to race in Gen4 after a successful recent test for Envision.
The 21-year-old joins new signing Guenther as current drivers Sebastien Buemi, who is retiring from Formula E, and Joel Eriksson depart the team.
He follows the likes of Taylor Barnard, Pepe Marti and Zane Maloney in exiting the F2 ladder to try to build a Formula E career.
O'Sullivan joined Guenther at Estoril in Portugal, as well as Jaguar drivers Antonio Felix da Costa and Stoffel Vandoorne, for the two day development test. A large contingent of Envision engineers were also in attendance.
O’Sullivan has been part of the Envision team since the start of 2025, shortly after he departed Williams's junior programme, and headed to Japan.
He took part in the rookie free practice session at 2025's Jeddah E-Prix, where he was hit by Jamie Chadwick in the final moments of running.
He then also took part in the rookie test day at Berlin last July ahead of an appearance at both the Miami and Jarama rookie days earlier this year. O’Sullivan has also appeared at several other E-Prixs this season assimilating to the team and to how E-Prixs are run.
Envision signed the experienced Guenther in July and is set to confirm each of their drivers publicly next month.
It will also open a newly extended headquarters at Silverstone later this year, including a new Dynisma simulator at its facility.
The team confirmed last month that it will continue with Jaguar as its power unit supplier, and is set to continue its small allocation of test days with the manufacturer next month.
Why Envision went all-change
The Envision team elected to do something it has never done before in its 12 season Formula E history – change both of its drivers.
Sylvain Filippi, the managing director of the team, with its chairman of the board Franz Jung, employed the all-change philosophy after seeing the team slump from teams’ champion in 2023 to an eight place finish last season and seventh this.
Since Nick Cassidy left for the Jaguar factory team at the end of the first Gen3 season in 2023, Envision has won a single race in Monaco in 2025 with Buemi. While flashes of pace and results punctuated the last two seasons, any consistency of top results was out of reach for the team.
Its technical relationship and partnership with Jaguar was ultra-close in 2023 but then cooled somewhat for the last three seasons. However, judging by the collaboration between the two at this month’s Estoril test, the close two-way partnership ethos has returned as Gen4 approaches.
Buemi will continue with the team for next season but only in a consultancy capacity which could be a potent hidden weapon for the team. Buemi also told The Race recently that he will continue to test the Gen4 car on occasion and offer a range of advice for the team.
“I'm going to attend the races without having that stress of the calendars, which is going to be actually quite nice for once,” said Buemi
“It's going to also be a year where we try to assess the value I can bring. The team has a lot of faith in me, thinking and really believing I can bring a lot of value. So, we'll see how next year goes and I'll attend a few races and then we'll see after for the future.”
Eriksson, who many feel was hard done by in not retaining his seat for Gen4, is speaking to several other teams.
The Swede could return to the Penske team with which he raced in Gen2 briefly. There are ongoing talks for Jaguar to supply powertrains to Penske.
