231 Area Code has 418 prefixes
| Prefix | Primary City | Carrier |
|---|---|---|
| 231-933 | Traverse City | Ameritech Michigan |
| 231-935 | Traverse City | Ameritech Michigan |
| 231-936 | Grand Rapids | Long Distance Of Michigan, Inc. Dba Ldmi - Mi |
| 231-937 | Howard City | Frontier North, Inc. - Mi |
| 231-938 | Acme | Ameritech Michigan |
| 231-941 | Traverse City | Ameritech Michigan |
| 231-942 | Grand Rapids | Cellco Partnership Dba Verizon Wireless - Mi |
| 231-943 | Traverse City | Ameritech Michigan |
| 231-944 | Traverse City | Cynergycomm.net, Inc. - Mi |
| 231-946 | Traverse City | Ameritech Michigan |
| 231-947 | Traverse City | Ameritech Michigan |
| 231-955 | Grand Rapids | New Cingular Wireless Pcs, Llc - Il |
| 231-970 | Grand Rapids | New Cingular Wireless Pcs, Llc - Il |
| 231-972 | Mecosta | Centurytel Midwest-midwest Inc Dba Centurylink |
| 231-974 | Grand Rapids | 123 Net, Inc. |
| 231-981 | Grand Rapids | Frontier North, Inc. - Mi |
| 231-994 | Grand Rapids | Acd Telecom, Inc. - Mi |
| 231-995 | Traverse City | Ameritech Michigan |