425 Area Code – Bellevue, Washington: Location, Time Zone & History

When Seattle's original 206 area code began running out of numbers as cell phones, faxes, and pagers proliferated, regulators split it three ways on April 27, 1997. The Seattle core kept 206, the South Puget Sound and Tacoma became 253, and the fast-growing suburbs north and east of Lake Washington — known locally as the Eastside — along with south Snohomish County, were assigned 425.

The territory covers Bellevue, Redmond, Kirkland, Everett, Renton, and Sammamish, and it grew into one of the Pacific Northwest's most important economic zones. Microsoft and T-Mobile are headquartered on the Eastside, and Boeing's Everett plant anchors a significant aerospace manufacturing presence. The region is also home to notable finance, retail and e-commerce, and biotechnology activity.

An overlay code, 564, was introduced for Western Washington starting in 2017, but as of late 2025 planning, 425 was not near exhaustion and no 564 numbers had yet been assigned within its territory. The 1997 split itself became local legend: the Seattle sketch show Almost Live! poked fun at Renton residents for preferring to be associated with the wealthier Eastside code rather than the less affluent 253.