'Slow Horses' Season 5 Sets a Track for September Arrival

Fans of Apple TV+'s Slow Horses, based on the Mick Herron thrillers The Slough House Series, prepare to ride out in the fall. The series, which has slowly built itself into one of Apple TV+'s most reliable and solid performers over four seasons, has set a return date for Season 5. It's perhaps the most telling release date from the streaming service, which has been working overtime in 2025 to build viewership after languishing behind the competition to the point that even FAST streamer Tubi was outperforming it.

Season 1 was given an Emmy Award season berth in April; Seasons 2 and 3 were moved to the December holidays for a better chance at the Golden Globes and SAG Awards. Season 4 was moved to the first week of September, a surprising choice, considering most streaming services routinely flaunt how little they rely on the traditional TV season. However, for Season 5, Apple TV+ is going ultra-conventional, with a premiere in the third week of September, a spot that only old-school broadcast shows like Grey's Anatomy still honor.

Season 5 will cover the events from Herron's fifth book, London Rules. This will be the last season to be drawn from a single book, at least for now, as Season 6 will combine the next two of the nine-book series, Joe Country and Slough House. Whether or not that's a sign Apple TV+ plans to wrap up the series with Season 7 remains to be seen, but only two books will remain unadapted by the end of 2026, 2022’s Bad Actors and the forthcoming Clown Town, which will land on bookshelves on September 9, 2025, two weeks before the Season 5 premiere. (Seasons 1 through 4 covered Slow Horses, Dead Lions, Real Tigers, and Spook Street.)