The new BBC Breakfast host hasn't yet been announced, but according to the Daily Star these are Ladbrokes' odds for the most likely candidates.
Jon Kay - 1/2
A familiar face to BBC Breakfast viewers, Kay has been a stand-in presenter for the main hosts since 2010.
The 52-year-old has worked on stories varying from the disappearance of Madeleine McCann to the trial of Shrien Dewani in South Africa, and was a London 2012 correspondent during the Olympics.
He's well known to both co-stars and viewers, and seems a likely choice to replace Walker.
Gethin Jones - 7/2
Although he's not from a news background, Jones certainly has a strong history with the BBC.
He's known for presenting The One Show and Morning Live, but could the 44-year-old be headed for an even earlier start in the near future?
Mike Bushell - 4/1
A more likely choice than Jones would be BBC presenter and sports reporter Bushell, who has more experience in news.
The 57-year-old has been working at the BBC since 1997, becoming familiar to Breakfast viewers for his segment trying out daring and unusual sports at the weekends.
Watch: Dan Walker bids farewell to BBC Breakfast
He's also known for his turn on Strictly where he fended off online abuse for staying in the contest as a viewer favourite for longer than some thought was warranted.
Jermaine Jenas - 5/1
What he lacks in news experience, Jenas could certainly make up for in sports reporting insights.
The former footballer, 39, often appears on TV as a pundit, but outside of football he's taken on more general presenting work for The One Show and made a documentary on knife crime for BBC Three, as well as one on football trolls for Channel 4.
AJ Odudu - 5/1
Again, Odudu might not have the news credentials of Walker, but she's certainly a TV favourite.
The 34-year-old presenter rose to fame hosting Big Brother's Bit On The Side, but became a BBC hit last year as a contestant on Strictly and gained breakfast show experience with a one-off revival of The Big Breakfast at Channel 4.
Ade Adepitan - 11/2
Wheelchair basketball player and TV presenter Adepitan, 49, is a popular choice for many a BBC show, where he's been a regular for nearly 20 years.
He's hosted sports programmes, documentaries, travel shows and even popped up on quiz shows - could he turn his talents to news?
Laura Tobin - 6/1
There's been a long-running rivalry between BBC Breakfast and ITV's Good Morning Britain, accelerated by BBC's Walker and GMB's former star Piers Morgan.
But now that Walker has left for Channel 5 and Morgan has started his new job at TalkTV, could Breakfast score another point over its rival by signing their weather reporter Tobin, 40?