Colin Farrell is technically yet to appear as Penguin in the upcoming DC film, The Batman by Matt Reeves. However, it seems that Warner Bros. has seen more than enough to invest in spin-offs based in the same universe. Case in point, Colin Farrell is returning to portray a younger Penguin as he rises through the criminal ranks of Gotham's underworld and goes from being just Oswald Cobblepot to becoming one of the city's most influential figures.
Where is The Penguin going to fit in the Batman timeline?
First off, don't think that The Batman is part of the DC Extended Universe. Matt Reeves' take on the Dark Knight, which sees Robert Pattinson take on the rule of the caped crusader, exists within its universe. So, we shouldn't expect to start seeing anyone else from the DCEU make their way to The Batman once the movie premieres on March 4, 2022.
As for The Penguin, it's effectively a prequel to The Batman. Since The Batman takes place in Bruce Wayne's sophomore year terrorizing the denizens of Gotham City, The Penguin will explore the years before this happened. Although the TV show will revolve around Farrell's portrayal of the facially scarred Gotham villain, we can expect a couple of several connections with The Batman.