One overlay now stretches across every legacy code in western Washington: 564 covers the combined territories of 360, 206, 253, and 425, and belongs to no single city. Numbers have been issued in the 360 region (Olympia, Bellingham, Port Angeles, Vancouver) since August 28, 2017, and Seattle’s 206 territory has been open to 564 assignment since June 10, 2025.
Ask where a 564 number is from and the honest answer is a half-state shrug. Every other Washington code answers with geography — 206 is Seattle, 509 is everything east of the Cascades. 564 answers with a date. The three digits carry a vintage, not an address: they mark the line as recent, and its owner as someone who ordered service somewhere between the Pacific coast and the Cascade crest.
Where the 564 area code actually is
The overlay’s legal footprint is the union of four legacy codes: 360 (the west side beyond the Seattle metro — Olympia, Bellingham, Port Angeles, Aberdeen, and Vancouver, the Washington city on the Columbia), 206 (Seattle plus its islands), 253 (Tacoma and the South Sound), and 425 (Bellevue, Redmond, Everett). Roughly the western third of the state, holding most of its population.
But footprint and issuance are different questions for 564, and that is the trap in looking it up. Numbers have flowed in the 360 territory since 2017, and the 206 region opened in June 2025 — so a 564 caller dials from Bellingham, Olympia, Vancouver, or, as Seattle’s 206 stock assigns out, the city itself. On NANPA’s April 2026 forecasts, 425 and 253 wait decades behind. The code-to-place instinct — see three digits, name a city — fails here by design; our area code guide covers how overlays weakened that instinct everywhere, and 564 breaks it completely.
The 1999 assignment and the 2000 master plan
NANPA assigned 564 on October 29, 1999. Planning Letter 196 scoped it as relief for 360 alone, with service to begin August 1, 2000. Nine months later the plan grew: Planning Letter 239, dated July 27, 2000, recorded the WUTC’s decision in docket UT-990219 to stretch the same code over all four western Washington codes at once, with the first 564 prefixes eligible for activation after October 20, 2001.
The industry got remarkably far. Permissive ten-digit dialing began September 1, 2000, and carriers stood up routing test numbers — dial 564-200-0564 and a recorded announcement in Bellingham confirmed your network could reach the new code, with siblings in Olympia, Bremerton, Vancouver, Aberdeen, Port Angeles, Monroe, and Mount Vernon. For about a year, 564 was a code that answered.
The eight-week reversal
Then, on August 28, 2001 — fifty-three days before the first real 564 prefix could have gone live — the commission suspended the entire project under docket UT-991535: the overlay and mandatory ten-digit dialing with it, until at least October 1, 2002. NANPA’s suspension notice, Planning Letter 298, runs a single page. The test numbers were slated for disconnection that November 30, and the pause announced as a year held for sixteen.
What changed was not demand but arithmetic. Under the original rules, a carrier entering a market claimed an entire prefix — 10,000 numbers — even to serve a few hundred customers, and the competitive rush of the late 1990s multiplied those claims across every rate center. Conservation measures, above all thousands-block pooling, cut that draw to 1,000-number blocks; our NPA-NXX breakdown walks through how many years of life the smaller unit buys. Exhaust forecasts kept receding, and the commission, monitoring prefix supply, never needed to restart the clock.
2016: the plan returns, smaller
On May 19, 2016, the WUTC approved relief once more — docket UT-143787, Order 01 — and NANPA’s Planning Letter 492 shows how sixteen years changed the design. The 2000 plan had opened all four codes at once; the 2016 plan would issue 564 numbers only in the 360 territory to start, holding the rest of the overlay in reserve.
Ten-digit dialing, though, could not be phased. Because the overlay legally spans the whole region, permissive ten-digit dialing began across 206, 253, 360, and 425 on January 28, 2017, and became mandatory on July 29, 2017. The code entered service on August 28, 2017 — nearly eighteen years after assignment — heralded by a routing test number with the driest wit in telecom: 564-564-1564.
Activation, one legacy code at a time
The 2016 relief plan contains the sentence that governs how 564 grows: the code may be assigned in the 206, 253, and 425 territories only when those codes are nearing exhaust. No flag day, no region-wide switch-on — each legacy code taps the shared overlay only when its own inventory runs down.
206 went first. The WUTC opened that phase with Order 1 in docket UT-230108 on June 15, 2023; from June 10, 2025 onward, a request for new service in the 206 territory may return a 564 number as 206 inventory assigns out. 253 and 425 still issue only their own digits until their exhaust dates approach. Existing numbers never change, and local calls remain local, even between a 206 and a 564 number.
Reading a 564 on caller ID
A 564 number certifies exactly three things. The line is relatively recent — no earlier than August 2017 in the 360 country, later still in Seattle’s, where assignment only opened in June 2025. It was issued in western Washington. And nothing narrower: a 564 caller is a Bellingham dentist, an Olympia agency, or a Vancouver contractor with equal plausibility — before long a Seattle startup too — and the code alone cannot separate them.
Even those weak signals are forgeable. Numbers port, VoIP places a Washington number anywhere on earth, and caller-ID spoofing can paint 564 onto a call from any origin. The signal that survives is cryptographic: calls signed at A-level attestation under STIR/SHAKEN carry a carrier’s verified claim about the caller — something three digits never managed.
Holding a 564 number on purpose
For businesses the overlay cuts both ways. A 564 line is every bit as local as its 360 or 206 neighbors — same rate centers, same local calling — and inventory is deep precisely because the code is young. Yet where local presence drives answer rates, many teams still want the code a market has recognized for decades: a 360 for Olympia, a 206 for Seattle while rate-center stock lasts. SIPNEX stocks local DIDs from both generations of western Washington codes and routes them into whatever PBX, softphone, or dialer you already run via SIP trunking.
Common 564 questions
Where is the 564 area code located?
Across western Washington. 564 overlays the territories of 360, 206, 253, and 425 — the Pacific coast to the Cascade crest. Numbers have been issued in the 360 region (Olympia, Bellingham, Port Angeles, Vancouver) since August 28, 2017, and the 206 region (Seattle and its islands) has been open to 564 assignment since June 10, 2025. The code names no single city; a 564 number can only be placed to one of the regions where the overlay is active.
What kept the 564 area code on the shelf from 1999 to 2017?
NANPA assigned 564 in October 1999 and Washington approved a four-code overlay in 2000, but conservation rules — chiefly thousands-block pooling, which hands carriers 1,000-number blocks in place of whole prefixes — kept the legacy codes supplied far longer than forecast. The commission suspended the project in August 2001, weeks before prefixes could activate; each fresh forecast pushed exhaust further out, and a 2016 order finally revived the overlay. Service began August 28, 2017.
Will the 253 and 425 regions get 564 numbers too?
Eventually, but on no announced date. The 2016 relief plan allows 564 assignments in the 253 and 425 territories only when those codes near exhaustion, and both hold decades of inventory — NANPA’s April 2026 forecasts run 425 into the 2040s and 253 into the 2050s. When either approaches exhaust, the WUTC opens its phase of the overlay — as it did for 206 with a June 2023 order and a June 10, 2025 start for assignments — and new lines there may then draw 564.
How local is a 564 number compared with a 206 or 360?
Fully local. Overlay numbers live in the same rate centers as the legacy codes beneath them, so a 564 line in Seattle behaves exactly like a 206 line for local calling, coverage, and rates — the WUTC’s implementation notice states plainly that local calls remain local between 206 and 564 numbers. The only real difference is vintage: a 564 number proves the line was created after the overlay reached its region.
Do carriers offer 564 numbers on request?
Yes. Carriers can provision 564 numbers wherever the overlay has live prefixes — across the 360 region since 2017, and in the 206 region as its own numbers assign out after the June 2025 opening. Businesses that prefer the legacy code a market has known for decades can still request 360 or 206 where rate-center inventory remains; both generations of codes work identically on modern SIP service.
Half the state now shares those three digits — your business just needs the one number that gets answered. SIPNEX, a direct FCC-licensed carrier, issues western Washington DIDs in 564 and its legacy siblings, holds its own RespOrg registration for toll-free service, and backs every number with dialer-ready SIP capacity — attesting each call at the A level on a STIR/SHAKEN certificate issued to SIPNEX itself, not to an upstream provider. Talk with the SIPNEX team, compare rates, or call (833) 665-2220.
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