With the deadline looming for Muni passengers to switch away from the paper version of the agency’s monthly "M" Fast Pass, Clipper card sales are picking up steam.

Starting in April, the agency’s M passes, which include unlimited service on all Muni lines, will be completely transitioned into the Clipper card, the Bay Area’s one-stop media fare.

About 65,000 passengers use the agency’s M pass, and during the last purchasing window, 42,850 riders had purchased Clipper cards to use as the monthly fare, according to the Metropolitan Transportation Commission, the agency in charge of the regional pass. That total marked a 13 percent increase from the previous purchasing window, according to the MTC. On March 28 alone, 1,500 M pass holders switched over to the Clipper card.

wreisman@sfexaminer.com