The Party Bus achievement in Halo Infinite has some of the more obscure requirements to complete it. Players must earn a "Mount Up" in a multiplayer match to get the Party Bus achievement. To get a Mount Up and the Party Bus achievement, players must drive a Razorback, honk the horn, and have three other players enter the vehicle afterward.
Razorbacks are the vehicles that resemble Warthogs but with no turret on the back. Razorbacks also have three passenger seats and a back compartment that can store weapons, items, or objectives.
To honk the horn: Press RT on Xbox, Left click on PC.
Waiting for three other players to get in the vehicle is difficult. If you have three party members, getting the achievement for everybody is easy, but if you are running solo, the best bet is to hope teammates get in. You can also hop into game chat to ask players to help you with the achievement.
Once the Razorback is full of passengers after honking, you should be awarded the Party Bus achievement.
For more Halo Infinite guides, check out How to get the New Kid on the Block Achievement in Halo Infinite on Pro Game Guides.
Bishop Lister is a writer and sports data analyst covering video games since 2019 after graduating from Arizona State University with a bachelor's in Sports Business, minoring in Digital Media Literacy. Bishop enjoys covering RPGs, sports, fighting, strategy titles, and FPS titles, with a focus on Apex Legends.