Area Code Atlas

NANP-Introduction of New 664 (Montserrat) Numbering Plan Area (NPA)

NPA 664 split from 809

Area code 664 was created for Montserrat in July 1996 as a split from area code 809, which had previously served all Caribbean islands. All existing central office codes and telephone numbers in Montserrat were transferred to the new code.

Permissive dialing period for 664 and 809

A permissive dialing period began on 1 July 1996 allowing calls to Montserrat to be completed using either area code 809 or the new 664. This period lasted until 1 June 1997, after which only 664 was used for new central office codes.

Mandatory dialing of 664 implemented

Mandatory dialing of area code 664 for calls to Montserrat was implemented on June 1, 1997, ending the permissive period during which both 809 and 664 could be used. After this date, only 664 was valid for Montserrat.

Montserrat transitioned to seven-digit numbers

Montserrat transitioned to seven-digit telephone numbers in May 2011, expanding the range of available central office codes and modernizing the local dialing system.