Saint Charles, MO is currently using one area code which is area code 636. Area code 636 was created from a split of area code 314 and put into service on May 22, 1999.
In addition to Saint Charles, MO area code 636 serves east-central Missouri including the larger cities and communities of Arnold, Ballwin, Chesterfield, Manchester, O'Fallon, St. Charles, St. Peters and Wildwood, in addition to many smaller communities within the area code 636 service area.
Saint Charles, MO is located in Saint Charles County and observes the Central Time Zone.
View our Times by Area Code tool.