NumberingData
Verified Nov 1, 2026 · Source: NANPA CO Code Assignment Records

SEASIDE prefixes in area code 503

NANPA records 5 assigned NXX blocks to rate center SEASIDE in area code 503, 0.6% of the 784 blocks assigned in the code. A rate center is the billing geography a block is allocated to – NANPA truncates the name to ten characters, so read it as a NANPA label rather than a town. 4 holders hold those blocks, the largest being QWEST CORPORATION (2), CELLCO PARTNERSHIP DBA VERIZON WIRELESS - OR (1), T-MOBILE USA, INC. (1). The earliest assignment on record here is 2001-12-03 and the most recent 2001-12-03. 5 of them are in thousands-block pooling, so those prefixes are shared between carriers in 1,000-number lots. The same rate center name also appears in area codes 910, 971 – overlay codes cover the same geography, so a rate center is served by all of them.

5 assigned blocks – 0.6% of 503
4 holders of record
5 of them pooled in 1,000-number lots

Prefixes assigned here

PrefixHolder of recordAssignedPooledIn service
503-440 Verizon CELLCO PARTNERSHIP DBA VERIZON WIRELESS - OR – yes yes
503-470 T-Mobile T-MOBILE USA, INC. 2001-12-03 yes yes
503-717 Lumen QWEST CORPORATION – yes yes
503-738 Lumen QWEST CORPORATION – yes yes
503-739 AT&T NEW CINGULAR WIRELESS PCS, LLC – yes yes

The holder is who received the block from the numbering administrator. It is not necessarily the carrier serving a given number: numbers move with their owners, and a pooled block is shared.

Who holds the blocks

HolderBrandBlocksShare here
QWEST CORPORATION Lumen 2 40%
CELLCO PARTNERSHIP DBA VERIZON WIRELESS - OR Verizon 1 20%
T-MOBILE USA, INC. T-Mobile 1 20%
NEW CINGULAR WIRELESS PCS, LLC AT&T 1 20%

Same rate center in other codes

Overlay codes cover the same geography, so one rate center is served by all of them.

Frequently asked

Which prefixes belong to SEASIDE in area code 503?

5 blocks: 440, 470, 717, 738, 739. The table above gives the holder of each.

Which carriers have numbers in SEASIDE?

QWEST CORPORATION (2 blocks), CELLCO PARTNERSHIP DBA VERIZON WIRELESS - OR (1 block), T-MOBILE USA, INC. (1 block), NEW CINGULAR WIRELESS PCS, LLC (1 block). These are the holders on record; the carrier actually serving a given number can differ, because numbers move with their owners.

Is SEASIDE a city?

It is a rate center – the unit NANPA allocates number blocks to. Its name is abbreviated to ten characters and is not necessarily a settlement: we print it as recorded rather than guess at the full name.

Other rate centers in 503

All 784 prefixes in 503