Area codes 510 and 341

In response to projections that 510 would exhaust in the second quarter of 2019, the California Public Utilities Commission approved the addition of an overlay area code, 341, to serve the East Bay.

By 2016, the California Public Utilities Commission (CUPC) projected that NPA 510 would exhaust its numbering pool by the second quarter of 2019.

In response, the commission held meetings in Berkeley, Oakland and Hayward in January and February 2017 to discuss area code relief for 510.

[2] The North American Numbering Plan Administrator (NANPA) proposed in May 2017 that CPUC relieve 510 by introducing the overlay area code 341 for the entire territory.

NANPA had previously assigned 341 as the relief area code for 510 in 1999, but nationwide number pooling procedures eliminated the need at that time.