Southeast of Trento, the San Martino di Castrozza ski area is a small ski center based around San Martino di Castrozza. There is bus service from surrounding villages and also withing the town of San Martino.
The San Martino di Castrozza ski area part of the Dolomiti Superski region which has over 1,200km of pistes spread over 12 valleys that served by 450 lifts. While a single skipass gives access to the Dolomiti Superski region, keep in mind that the 12 valley are not all interconnected and you may need bus transport between valleys. Also, the snowfall in this southernly ski region is known to vary greatly season to season. Keep in mind that there is limited off-piste snowboarding in the Dolomiti Superski region -- it is prohibited in most areas and guides are highly-recommended in the others.
Overall, San Martino di Castrozza is the 25th most popular snowboard & freeride destination of all 40 snowboarding resorts in Italy.