Like other cities in the northeastern part of the state, Williamsport uses the 570 area code that was created in 1994 after splitting from the original 717 area code for Pennsylvania. The 570 code serves Williamsport and surrounding areas specifically in the north-central and northeast parts of the state.

Nearby codes are 814 to the west and 607 in New York. Having a local 570 area code number helps businesses in Williamsport establish ties to the regional community.