Prior to the 2015 season, Bamber signed with Porsche Motorsport as a works driver. In January 2015, he and fellow works drivers Jörg Bergmeister and Frédéric Makowiecki took the No.912 Porsche 911 RSR to seventh place at the 24 Hours of Daytona. Bamber and Nick Tandy joined Formula One driver Nico Hülkenberg in the Porsche LMP squad to contest the 6 Hours of Spa-Francorchamps and the Le Mans 24 Hours in a 919 Hybrid. Bamber's hybrid, car No. 19, was third on the grid after Porsche finished first, second and third in qualifying, but ended up winning comfortably. Bamber's childhood friend and Porsche teammate, Brendon Hartley, with co-drivers Mark Webber and Timo Bernhard, started from second on the grid in a 919 Hybrid and finished the race in second place. Bamber claimed his first career GT Le Mans (GTLM) pole at the Continental Tire Road Race Showcase at Road America in his first qualifying attempt as a Porsche factory driver on August 8. He bettered the previous lap record by more than a full second. He also made a guest appearance in the FIA World Endurance Championship's 6 Hours of Nürburgring, filling in for Klaus Bachler in the No. 88 Abu Dhabi-Proton Racing Porsche 911 RSR. Bamber made his debut in the FIA GT World Cup in the streets of Macau in November. The versatility in going between LMP1, GTE-Pro (GT Le Mans in IMSA) and GTE-Am this year, he said, made him a better driver.