Area Code Atlas

NANP-Introduction of New 670 (CNMI) Numbering Plan Area (NPA)

Planning letter issued for NPA 670 introduction

A planning letter was issued on September 4, 1996, announcing the introduction of area code 670 for the Northern Mariana Islands. This marked the formal start of preparations for the territory's integration into the North American Numbering Plan.

NPA 670 became effective for the Northern Mariana Islands

Area code 670 became effective on July 1, 1997, when the Northern Mariana Islands joined the North American Numbering Plan. The new code replaced access via the ITU country code 670, enabling domestic-rate calling between the CNMI and the United States.

Permissive dialing period began for NPA 670

A permissive dialing period for area code 670 began on July 1, 1997, allowing both the new NANP area code and the former ITU country code 670 to be used for calls to the Northern Mariana Islands.

Mandatory use of NPA 670 began

Mandatory dialing of area code 670 began on July 1, 1998, ending the permissive period during which both the NANP area code and the ITU country code 670 could be used for calls to the Northern Mariana Islands.

Country Code 670 Assigned to East Timor