Additionally, Stephen Graham and Sean Delaney have been cast in undisclosed roles.
During the long development of the 2018 film Venom, the character Carnage was expected to appear as an antagonist. During pre-production on that film, the creative team decided not to include the character so they could focus on introducing the protagonists, Eddie Brock and Venom. Director Ruben Fleischer felt that leaving Venom's most formidable villain for a sequel would give the franchise "a place to go" and would be a natural next step, so Carnage's alter-ego Cletus Kasady was introduced in a mid-credits scene at the end of the first film with the intention of featuring him in a sequel. Fleischer wanted to cast Woody Harrelson in the role, feeling there was a "natural connection" between the character and Harrelson's performance in Natural Born Killers, and asked Harrelson while the pair were discussing a sequel to their film Zombieland. After meeting with Fleischer and Tom Hardy—who portrays Brock and Venom—for dinner, Harrelson agreed to take on the part. Harrelson described his decision as a roll of the dice since he was unable to read a script for the sequel before signing on to the first film. In August 2018, ahead of Venoms release, Hardy confirmed that he had signed on to star in two sequels. At the end of November 2018, Sony gave an October 2, 2020 release date to an untitled Marvel sequel that was believed to be Venom 2, which would place the film in the same release timeframe as the first Venom; box office analysts believed by then that Venom had been successful enough to guarantee a sequel would be made. A month later, Venom writer Jeff Pinkner confirmed that a sequel was "happening", but he was not involved in writing it at that point. Fleischer reiterated this, saying that he could not discuss a sequel but he saw the first film as Brock and Venom "coming together. So there’s a natural evolution from that to like, okay, now what’s it like to live together? It’s like a bromantic sort of relationship." In January, Kelly Marcel signed a "significant" deal with Sony to write and executive produce the sequel after also working on the script for the first film. This marked the official beginning of work on the film for the studio, and was revealed alongside confirmation of Avi Arad, Matt Tolmach, and Amy Pascal returning as producers. Hardy and Harrelson were also expected to return for the sequel, along with Michelle Williams in the role of Brock's ex-fiancée Anne Weying. No director was confirmed for the film, with Sony considering replacing Fleischer due to his commitments to , though he still intended to be involved in Venom 2. By the end of July 2019, Sony hoped for filming to begin that November and had met with several candidates to replace Fleischer as director since he was still completing work on Zombieland: Double Tap at that time; directors the studio met with include Andy Serkis, Travis Knight, and Rupert Wyatt. Sony was also interested in Rupert Sanders directing the film, but that "didn’t work out". Serkis confirmed at the start of August that he had discussed the project with Sony and it was "potentially something that might happen", shortly before he was officially hired to direct the film. Serkis was partly hired due to his experience working with CGI and motion-capture technology as both an actor and director. Discussing the film soon after his hiring, Serkis said Hardy had been working closely with Marcel on the screenplay which was "centered around their take". Fleischer said he was happy to let Serkis take over the franchise following the negative critical reaction that the first film received, believing reviewers had unfairly treated the "crowdpleasing movie", potentially due to biases against Sony and towards Marvel Studios' rival superhero films. By the time Serkis was hired, Hutch Parker had joined the sequel as a producer. A friend of Sony Pictures chairman Tom Rothman, Parker previously served as a producer for several Marvel-based films produced by 20th Century Fox.
In September 2019, Reid Scott was expected to reprise his role as Weying's boyfriend Dan from the first film. The character Shriek was also expected to appear as the film's secondary villain and a love interest for Carnage. Many different actresses were looked at for the part, before Naomie Harris was cast in the role in mid-October. Stephen Graham had also joined the film, in an undisclosed role, by the end of the year. Tolmach said there was a chance the sequel could be rated R following the success of the R-rated Joker, as well as previous successful R-rated comic book films such as Deadpool and Logan. However, Tolmach cautioned that the PG-13 rating of the first Venom had led to box office success and they would not be looking to change the franchise's tone simply because it had worked for others. He added that the biggest lesson learned from the first Venom was that fans loved the relationship between Brock and Venom, and the sequel would focus more on the two characters together because of this.
Post-production for the film began shortly before many film productions were forced to shut down due to the COVID-19 pandemic, with Serkis beginning work editing the film in London with the editorial department. Once post-production had to be shut down, the film's editor returned to the United States and began working with Serkis remotely to finish editing the film. Actor Sean Delaney revealed in early April 2020 that he had a "very small blink-and-you'll-miss-me role" in the sequel, while Sony confirmed that the film was scheduled to be released on October 2, 2020 and was intended to keep that release date despite the pandemic. Later that month, Sony moved the film's release date to June 25, 2021 after that date became available due to other COVID-19 related delays. Sony also announced the film's title as Venom: Let There Be Carnage. Serkis felt the delay would give more time to improve the film's visual effects, and would help ensure that audience members would be comfortable with going to see the film in theaters.
After announcing the film's official title in April 2020, Sony also released a short teaser featuring the official logo for the film. Many fans of the Venom comic books criticized the title, with some wondering why the comic book storyline title Maximum Carnage was not used. Sam Barsanti of The A.V. Club also thought Maximum Carnage would have worked better, or even Venom 2, and compared the official title to films like ', The Assassination of Jesse James by the Coward Robert Ford, and '. /Films Ethan Anderton acknowledged these criticisms, but felt it was a great title given the first film was "surprisingly goofy". Vinnie Mancuso at Collider agreed, calling it "the perfect title for a beautifully stupid franchise". He said it suggested Sony "knows the kind of property it has on its hands". Tom Reimann, also at Collider, described the teaser as Sony "proudly showing off the logo of the new film as if the title isn't completely insane".
Venom: Let There Be Carnage is scheduled to be released in the United States on June 25, 2021, in IMAX. It was previously scheduled for October 2, 2020, but was delayed to the June 2021 date due to the COVID-19 pandemic.
Hardy confirmed in August 2018 that he had also signed on to star in a third Venom film.