Running every Friday and weekend, the seasonal minibus route enables walkers and day-trippers to travel between Hawes, Tan Hill, Arkengarthdale, and Reeth without driving along narrow mountain passes.
Coordinators say the trial service is helping reduce traffic congestion and parking pressure at popular fell parking spots.
Passengers can pre-book seats online or pay on board, with strong uptake reported from hikers tackling high-altitude valley routes.