Which areas will the S3 line connect?

The S3 line will connect Shoreline South Station to Bothell via Kenmore and Lake Forest Park.

What are the features of the new S3 line stations?

The new S3 line stations will feature real-time arrivals information, large comfortable shelters, and improved infrastructure to enhance passenger experience.

How frequently will the S3 buses operate?

The S3 buses will operate every 10 to 15 minutes and will be available up to 19 hours a day.

What environmental benefits does the S3 project offer?

The S3 line will use a fleet of battery-electric buses, contributing to zero-emission public transportation and reducing the environmental impact.

Seattle's Sound Transit Breaks Ground on S3 Bus Line

S3 will connect communities along SR 522 with fast, reliable, battery-electric bus service from Shoreline South Station to Bothell via Kenmore and Lake Forest Park.

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March 2, 2026

Stickers and a paper bus for S3 bus line — S3 will operate every 10 to 15 minutes up to 19 hours a day with transit signal priority and infrastructure improvements that will cut travel times from up to 59 minutes today to as low as 35 minutes when the project is complete.
Credit:
Sound Transit

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Sound Transit's new S3 line will provide battery-electric bus service connecting Shoreline South Station to Bothell via Kenmore and Lake Forest Park.
The project includes the construction of 14 new stations, enhanced travel infrastructure, and improvements to intersections and sidewalks along the route.
The S3 line aims to reduce travel times significantly, operating every 10 to 15 minutes with enhancements like transit signal priority.

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Seattle Sound Transit and project partners celebrated the groundbreaking of Sound Transit’s Stride S3 line.

S3 will connect communities along SR 522 with fast, reliable, battery-electric bus service from Shoreline South Station to Bothell via Kenmore and Lake Forest Park.

Sound Transit’s S3 Line

The project will deliver 14 new stations featuring real-time arrivals information and large, comfortable shelters. The S3 line will be operated by a fleet of 15 60-foot battery-electric buses. The project will also feature new BAT lanes, sidewalks, plantings, and intersection improvements along the corridor.

S3 will operate every 10 to 15 minutes up to 19 hours a day with transit signal priority and infrastructure improvements that will cut travel times from up to 59 minutes today to as low as 35 minutes when the project is complete.

“This investment in fast, reliable, zero-emission bus rapid transit meets the moment for north Lake Washington communities,” said Sound Transit CEO Dow Constantine. “Stride will provide a consistent connection between all the cities along the rapidly developing 522 corridor, and to our regional light rail system.”

Q&A

The S3 bus line aims to provide fast, reliable, battery-electric bus service connecting communities along SR 522, reducing travel times and promoting eco-friendly transportation.