Boyle has declared his wish to make a sequel to Trainspotting which would take place nine years after the original film, based on Irvine Welsh's sequel, Porno. He was reportedly waiting until the original actors themselves aged visibly enough to portray the same characters, ravaged by time; Boyle joked that the natural vanity of actors would make it a long wait. Ewan McGregor stated in an interview that he would return for a sequel, saying "I'm totally up for it. I'd be so chuffed to be back on set with everybody and I think it would be an extraordinary experience.".
In 2013, Boyle said he wants to make a sequel that would be loosely based on Porno which he has described as "not a great book in the way that Trainspotting, the original novel, is genuinely a masterpiece". Boyle says that if the sequel happens 2016 would be the release.
In July 2013 at the San Diego Comic-Con, Carlyle confirmed that the sequel will happen.
In an interview for Detail magazine, McGregor said the following regarding the sequel: "It looks like it might happen. The idea is that we shoot it in 2016, which would be 20 years after the original came out."
On 6 May 2014, during a BBC Radio interview with Richard Bacon, Welsh confirmed that he had spent a week with Boyle, Andrew McDonald and the creative team behind Trainspotting to discuss the sequel. Welsh stated that the meeting was in order to "explore the story and script ideas. We're not interested in doing something that will trash the legacy of Trainspotting... we want to do something that's very fresh and contemporary."  Welsh did not however confirm any kind of timeline for the film, unlike Boyle's comments about wanting the film to come out in 2016.
But in a newspaper interview with The Scotsman on 17 November 2014, Welsh revealed that McGregor & Boyle had resolved their differences and had held meetings about the film, saying "I know Danny and Ewan are back in touch with each other again. There are others in the cast who’ve had a rocky road, but now also reconciled. With the Trainspotting sequel the attention is going to be even more intense this time round because the first was such a great movie - and Danny’s such a colossus now. We’re all protective of the Trainspotting legacy and we want to make a film that adds to that legacy and doesn’t take away from it."