The SNP will decide on a replacement for outgoing Westminster leader Ian Blackford at the party’s annual general meeting on Tuesday.
Stephen Flynn and Alison Thewliss both announced their candidacy for the role set to be vacated by the Ross, Skye and Lochaber MP.
Blackford spent more than five years in the job, however, along with deputy Kirsten Oswald, has now opted to depart after taking up a new role working on the business case for Scottish independence.
In an early tweet on Tuesday morning, he wished his successor luck and thanked colleagues.
Blackford wrote: “Today is my last day in office for the SNP as Westminster leader.
“Thank you to colleagues for the opportunity to serve both MPs and staff as well as all those who have supported and encouraged me. Good luck to my successor as look I forward to my next challenges.”
It comes just weeks after Flynn, the party’s energy spokesman, was forced to deny rumours he was mounting a “coup” against Blackford after a fractious few months under his leadership.
The Aberdeen South MP revealed his candidacy for the vote, which takes place on Tuesday, in a Twitter post on Sunday evening, pledging to be a “strong voice” for Scotland at Westminster.
Flynn, who has suffered from a serious condition called avascular necrosis since he was a teenager, is yet to announce a deputy but reports suggest he wants Mhairi Black to take on the role.
“Few working class folk ever make it to parliament, fewer still run to be political leaders.
“Even fewer do so having spent almost the entirety of their teenage and adult years battling a physical disability.
“Your experiences tend to shape you and I am no different.”
Thewliss meanwhile announced she was standing for the position with Stuart McDonald as her number two.
The Glasgow Central MP previously said she had “no intention” of running, but felt a “duty” to step up on the confirmation of Blackford’s departure.
“I’ve been working for independence for over half my life. Scotland is closer to achieving that now now than ever before,” she said after revealing her candidacy.
“The Westminster group needs a leader who can build on Ian’s achievements and demonstrate that independence, far from being abstract, is the alternative to Brexit, the cost of living crisis and Tory austerity.”
Blackford insisted he still “absolutely had respect” of his MPs, despite rumours of a mutiny within the Commons group.
He previously faced calls to resign for his handling of misconduct allegations against SNP MP Patrick Grady who was found to have made an “unwanted sexual advance” towards a party worker at a social gathering in 2016.
Grady’s victim told STV News that staff working for the SNP in Westminster “remain unsafe” with Blackford in charge.
At the time, the SNP said it was acting to support all its staff in line with its duty of care.
But Blackford said there was “strength of unity” among the Westminster group, adding the party was fully committed to pushing towards the “de facto” referendum at the next general election.
“I have been the leader of the SNP for the last five and a half years,” he told STV News last week.
“I put myself up for election every year. I have commanded their respect and I believe I absolutely have the respect of my colleagues in the Westminster group as I have done and will do so in the role I have now going to play supporting all of them and supporting the journey towards independence.”