The state of Iowa is divided into five numbering plan areas (NPAs) in the North American Numbering Plan (NANP), with one area code assigned to each. None of the NPAs are expected to experience central office code exhaustion in the immediate future. It is one of the few states that has not implemented an overlay complex in any of its areas.
| Area code | Year | Parent NPA | Numbering plan area |
|---|---|---|---|
| 319 | 1947 | – | Cedar Rapids, Waterloo, Iowa City, and Cedar Falls |
| 515 | 1947 | – | Des Moines, Ames, West Des Moines, Urbandale and Fort Dodge |
| 712 | 1947 | – | Sioux City, Council Bluffs |
| 641 | 2000 | 515 | Marshalltown, Mason City, Ottumwa, Tama |
| 563 | 2001 | 319 | Davenport, Dubuque, Bettendorf, Clinton, Muscatine |