On January 23, 2021, Dubois was traded with a 2022 third-round pick to the Winnipeg Jets in exchange for Patrik Laine and Jack Roslovic. The 2020–21 season was played in a specialized format due to the COVID-19 pandemic, with the Jets part of the all-Canadian North Division, and Dubois had to quarantine for two weeks upon arrival, limiting his training and preparation time. He sustained an injury in only his second game with the team, missing four games as a result. On February 21, in just his third game with the Jets, Dubois scored his first two goals as a Winnipeg Jet in a 4–3 overtime Jets win against the Vancouver Canucks. Dubois' second goal of the game was the overtime winner. Dubois also scored an assist in the same game, coincidentally doing the same thing that Laine did in his last game as a Winnipeg Jet (scoring 2 goals and 1 assist, with one of the two goals coming in overtime). The season ultimately proved disappointing for both Dubois and the Jets. The team qualified for the 2021 Stanley Cup playoffs, but after sweeping the Edmonton Oilers in the first round they were swept in turn by the Montreal Canadiens in the second. Another injury prematurely concluded Dubois' regular season, and delayed his playoff debut against the Oilers. He managed only eight goals and twelve assists in 41 games in the regular season, ending a 24-game goalless streak. He fared little better in the postseason, with only three assists in seven games Dubois said afterward "I know I can be a lot better. This year was my fourth year in the NHL. I'm really happy with my first three."
