Spider-Man: Beyond the Spider-Verse was originally meant to release some time in 2024, shortly following the release of Spider-Man: Across the Spider-Verse. However, people working on the film made it very clear that would not be happening, and over the course of multiple delays the film was instead pushed back to a June 2027 release.
Chris Miller and Phil Lord are aware of how delayed the film is, and explained the decision of pushing it back so far. Speaking with io9 (via Gizmodo), Miller said that originally the movie was just too big. "At one point it was one movie, but there was too much movie there, so it was separated into two," he said. "But then once you looked at that second half of a movie, you're like, 'Well, that's like not just a story arc that has a beginning, middle, and end."
"There's no one that puts more pressure on us than ourselves, wanting to outdo ourselves each time and see things that you haven't seen before and make it feel like something you've never experienced before," Miller added. "And so, trying to get something that is as worthy as the previous two has been the driver... Having to take it apart to put it back together again was really, really [the] real thing that made it take longer."
Miller and Lord have also been working on Project Hail Mary with Ryan Gosling, which is set to release in theatres on the 20th of March. In the meantime, the team at Sony Pictures Animation is firing on all cylinders to get the third Spider-Verse movie out and keep it from getting delayed again.