Jodie Whittaker will leave Doctor Who after the season 13 and three specials, but why is she stepping away from the TARDIS? Whittaker was cast as The Doctor back in 2017, taking over from Peter Capaldi when he regenerated in that year's Christmas Special. Whittaker has so far played the Thirteenth Doctor for two full seasons and three New Year's Day Specials, but her tenure is about to come to an end.
As announced on July 29, 2021, both showrunner Chris Chibnall and Whittaker will leave Doctor Who after the six-episode miniseries that makes up season 13, and then three specials to air in 2022, with one on New Year's Day, one in the spring, and one in the fall. There's still plenty for Doctor Who to accomplish in that time, especially to wrap-up Thirteen's story and the fallout from the Timeless Child reveal. Still, Whittaker's departure has been rumored for some time, and looking at her exit there are a few possible reasons.
Chiball and Whittaker are stepping down at the same time, having previously decided that they would enter and exit the show together, but that itself raises the question of why anyone needed to leave. Unfortunately, Doctor Who's future and what it needs to survive (and indeed, some calls for it to end), and so allowing a new writer and actor to take over the TARDIS at this juncture is a logical step.
For both Whittaker and Chibnall, alongside the quality and the fact people may wish to move on and freshen things up, there are also the demands of the show. This is something previous Doctor Who actors have spoken about, with the filming needs - alongside the publicity side of things and constant attention - proving a drain on many an actor and limiting opportunities elsewhere. That's not necessarily what's happened with Whittaker, but the actress is notably leaving after three seasons, following in the footsteps of all the other modern Doctor Who actors with the exception of Christopher Eccleston (who had just the single season). Even aside from the demands, regeneration and constantly refreshing things are baked into the fabric of the show, so it's unlikely any modern Doctor would last for much longer.
Chibnall and Whittaker had a strong working relationship even before Doctor Who, thanks to ITV drama series Broadchurch, and so it's easy to understand why they'd want to, as Whittaker put it, "ride this wave together." It is, however, something of a shame to see Whittaker depart. While Chibnall's writing has missed the mark at times and the overall quality has been hit and miss, Whittaker has proven to be a great Doctor, full of the wonder, optimism, weirdness, and sheer goodness that makes the character so special and so enduring. It would've been great to see what she could do under another showrunner, but hopefully her final run of episodes can make for a fitting conclusion to her time as the Thirteenth Doctor before she regenerates.