Green Party co-leader Jonathan Bartley will run again for the leadership on a joint ticket with former London mayoral candidate Sian Berry.
His current co-leader Caroline Lucas announced this week she would not stand again in this summer’s election.
The Brighton Pavilion MP and Mr Bartley have shared the leadership since 2016.
Ms Berry, a London Assembly member who came third in the 2016 mayoral election, tweeted that she was “very pleased” to be standing.
Their campaign website pledges a “fiercer Green resistance” on issues like fracking, immigration detention and HS2 – the planned high-speed rail network – as well as “bigger Green successes”.
Leaders of the Green Party of England and Wales are elected for two years and an election is due to take place this summer. Nominations opened on Friday and the result will be announced in September.
Ms Lucas, the party’s only MP and best-known politician, announced earlier this week that she would not be standing for re-election, and would be “focusing even more” on her work in Parliament and her constituency.
Across the 150 councils holding elections in May, the Greens ended with 39 councillors, a net gain of eight seats – but lost five of their 10 seats in Norwich.
At the time Ms Lucas acknowledged her party had been “hurt” by voters moving to Jeremy Corbyn’s Labour but said they had “held our own and made some significant gains”.
Activist and campaigner Ms Berry, 43, has twice run to become London mayor, knocking the Lib Dems into fourth place in 2016 and was the party’s “principal speaker” from 2006 to 2007.
Mr Bartley, who was elected to Lambeth council in May, said: