Yelloly moved into the IMSA SportsCar Championship for the 2023 season, becoming part of the BMW M Team RLL works team which entered a BMW M Hybrid V8 into the GTP category. Throughout the season opener at the 24 Hours of Daytona, technical issues would plague the outfit, which went on to finish 49th overall after an early hybrid system problem forced the Nr. 25 car to spend two and a half hours behind the pit wall. The team bounced back in Sebring, where, having engaged in battles with other cars in the category for the majority of the race, Yelloly profited from a collision between the #10 Acura and the pair of Porsche 963s ahead to take second place, BMW's first podium in the GTP era. At the Grand Prix of Long Beach, Yelloly managed to set the fourth-quickest laptime, thus achieving the team's best qualifying result up to that point. The race itself proved to be frantic, with Yelloly tapping the Acura of Tom Blomqvist into a spin at the first corner and keeping third place until the mandated driver change afterwards. Teammate Connor De Phillippi fought for a spot on the podium for the remainder of the contest, eventually securing another runner-up finish after a late-race crash from Ricky Taylor.
