Located in the Eastern (GMT -05:00) time zone. Area code 631 serves the state of New York. This area code was assigned on May 5th, 1999. On November 1st, 1999 it went into service. 631 is a General Purpose Code. 631 service area does overlap with 934 area codes. Dialing pattern for local calls within the same NPA (area code) is 10D.