Airports prior to construction of the third runway The largest airport in the region is
Seattle–Tacoma International Airport in
SeaTac, a major
international airport that serves as a commercial hub for
Alaska Airlines and
Delta Air Lines. It is operated by the
Port of Seattle and lies between Seattle and Tacoma; both cities contributed financially to its construction, which was completed in 1944 for military use and later expanded for commercial aviation. Sea-Tac served 46 million passengers in 2023 and was the 11th busiest airport in the United States and 28th busiest in the world by passenger volume. , the airport has 91 domestic destinations and 28 international destinations in North America, Asia, Europe, and Oceania. The area's other conventional passenger airport is
Paine Field in Everett, north of Downtown Seattle. The airport is owned by the Snohomish County government and primarily used for general aviation and various industries, including the nearby
Boeing Everett Factory. The passenger terminal, operated by a private company, opened in 2019 and serves domestic destinations, primarily in the Western United States. , Alaska Airlines is the sole airline at Paine Field and serves up to eleven destinations during peak seasons. The state legislature convened a new commission in 2019 to search for a suitable site for a reliever airport, which could include expansion of Paine Field or construction of an outlying airport by 2040. The commission identified four sites in the southern Puget Sound region but was dissolved before a final recommendation due to public opposition to a new airport. Limited passenger service is also available from
Boeing Field in Seattle, which primarily serves cargo and charter traffic.
Kenmore Air, a passenger
floatplane operator, serves two airports in the area: the
Kenmore Air Harbor Seaplane Base on
Lake Union in Seattle and
Kenmore Air Harbor on
Lake Washington in
Kenmore. The metropolitan area's other general-use airports include
Arlington Municipal Airport in northern Snohomish County;
Bremerton National Airport in Kitsap County; the privately owned
Harvey Airfield in
Snohomish; and
Renton Municipal Airport, adjacent to Lake Washington and the
Boeing Renton Factory.
Roads and highways The Seattle area has a
grid-based road system that originates at designated points in each of the three counties; streets and roads are
numbered from this origin point with cardinal directions as prefixes or suffixes. The origin for the King County grid is
1st Avenue and Main Street in
Downtown Seattle; from there, numbers increase outward until they reach the county border and reset. The northernmost street in King County is Northeast 205th Street, which runs along the county line and is known as 244th Street Southwest in Snohomish County. Cities are permitted to have separate numbering and naming systems for streets, In addition to streets and roads under the jurisdiction of the local and county governments, the state legislature designates a network of
state highways that are maintained by the
Washington State Department of Transportation (WSDOT). These highways are primarily funded by the state government through a
fuel tax and annual fees on
vehicle registration that are collected by other departments. Several highways connect beyond the Puget Sound region, including crossings of the Cascade Mountains through
mountain passes—of which three have winter access during normal weather. Some city streets in the state highway system, such as Aurora Avenue North on
State Route 99 (SR 99), have shared jurisdiction or ownership between WSDOT and local governments. The state highway system comprises undivided highways as well as
controlled-access freeways, which include several routes on the national
Interstate Highway System that cover a total of in the Seattle metropolitan area. These freeways were built by the state government in the 20th century to conform with
standards set by the
Federal Highway Administration and are numbered as part of a national scheme. The main
West Coast freeway,
Interstate 5 (I-5), travels through the region and serves the cities of Tacoma, Seattle, and Everett; its busiest section in Downtown Seattle carried 274,000 vehicles on an average day in 2016, while approximately 2.6 billion person miles were traveled on the corridor between
Federal Way and Everett in 2017. The only east–west Interstate in the area is
I-90, which connects Seattle to Bellevue, Issaquah, and Eastern Washington via
Snoqualmie Pass. and
I-705, a short spur into Downtown Tacoma that opened in 1990. Other major freeways in the area include
SR 16 from Tacoma to the Kitsap Peninsula;
SR 18 from Federal Way to Snoqualmie;
SR 167 from Puyallup to Renton;
SR 509 from SeaTac to Seattle;
SR 520 from Seattle to Redmond;
SR 522 from Bothell to Monroe; and
U.S. Route 2 (US 2) from Everett to Snohomish. The highway system includes several of the longest
floating bridges in the world due to the depth of local water bodies and their soft silt, which make conventional bridge designs more challenging.
Lake Washington has three of the bridges: a pair carries separate directions of I-90, while the
Evergreen Point Floating Bridge carries SR 520 and is the world's longest floating bridge at . The SR 520 floating bridge is one of two
toll bridges in the area, along with the eastbound span of the
Tacoma Narrows Bridge on SR 16, which was constructed with toll revenue. The toll bridges and the
State Route 99 tunnel in Seattle use the
Good to Go electronic toll system, which charges based on a transponder or by reading a vehicle's
license plate with fees collected by mail. The region's freeway system includes a network of
high-occupancy vehicle lanes (HOV lanes) to encourage use of mass transit and
carpools during
peak periods; the lanes also include bypasses at
ramp meters and special ramps at some interchanges. , of the planned in the network have been constructed and carry 38 percent of all freeway miles traveled. A section of HOV lanes on I-405 and SR 167 are planned to be converted to
high-occupancy toll lanes (HOT lanes) by the late 2020s. The Good to Go system is used to collect tolls for single-occupant vehicles in the lanes and are set by variable demand with a maximum of $15; vehicles carrying three or more people are exempt from the toll with a compatible transponder.
Railroads The region is served by two
Class I railroads primarily used for freight:
BNSF Railway, which owns several lines that connect the north–south I-5 corridor and across the Cascade Mountains; and the
Union Pacific Railroad, which owns a short section from Tukwila to Tacoma and has operating rights on other BNSF lines.
Amtrak operates intercity passenger trains on these railroads with stations in the Seattle metropolitan area. The
Cascades serves the Portland–Seattle–Vancouver corridor with multiple trips per day; the
Coast Starlight operates daily service to Oregon and California from
King Street Station in Seattle; and the
Empire Builder connects the region to Eastern Washington and
Chicago.
Mass transit train on the
2 Line in
Bellevue The Seattle metropolitan area has seven major transit agencies that provide
public transportation across several modes, including buses,
light rail,
commuter rail, and
ferries. Most transit modes in the region use the
ORCA card, a smart fare card system introduced in 2009. Fares are discounted for people aged 65 or older or those with disabilities; since 2022, all fares for passengers 18 years old and younger have been waived as part of a state program. According to 2019 estimates from the
American Community Survey, approximately 10.7 percent of workers in the Seattle metropolitan area used public transit to commute—the sixth most per capita among the largest metropolitan areas in the United States. The high ridership, particularly for buses in the 2010s, was attributed to subsidized fares and other benefits offered by large employers for commuters.
Sound Transit is a regional authority that manages
Link light rail,
Sounder commuter rail, and
Sound Transit Express buses on freeways. It was created in 1993 and has a district that covers and 2.9 million people across 50 municipalities. Link, the regional
rapid transit system, carried 23.9 million passengers in 2022 on its two lines: the
1 Line from Seattle to
SeaTac, and the
T Line in Tacoma. Sound Transit's major capital projects are funded by several sources, including
property taxes and fees on motor-vehicle registrations, that are enabled by
ballot initiatives approved by voters in 1996, 2008, and 2016. The light rail system plans to expand to by 2045 and cover several major corridors at a total cost of $149 billion. and the
Seattle Center Monorail, a popular tourist attraction that carries 2 million riders annually. The largest local transit agency is
King County Metro, which operates buses,
paratransit,
vanpools, and
rideshare in King County. It also operates an
electric trolleybus network in Seattle as well as the city's streetcar system. Metro is one of the largest bus agencies in the United States by ridership, carrying 63.6 million annual passengers in 2022. Other providers include
Pierce Transit in Tacoma and Pierce County;
Kitsap Transit in Kitsap County; and
Intercity Transit in Olympia and Thurston County, which operates fare-free.
Ferries fleet, on the
Mukilteo–Clinton route The state-run
Washington State Ferries system is the largest maritime transit system in the United States and carries both passengers and vehicles as an extension of the state highway system; it also serves as a tourist attraction in addition to its role as a commuter mode. The ferries carried 17.4 million passengers and 8.6 million vehicles in 2022; prior to the COVID-19 pandemic and service cuts, it had carried 25 million annual passengers. The system was created in 1951 after a state takeover of the
Puget Sound Navigation Company's main lines in the region.
Vashon Island has two terminals at opposite ends of the island: the north terminal is used by the
Southworth–Vashon–
Fauntleroy triangle service that connects east to
West Seattle; and the south terminal at
Tahlequah is part of the
Point Defiance–Tahlequah route from Tacoma. Two routes serve Snohomish County: the
Edmonds–Kingston run connects to the Kitsap Peninsula and the
Mukilteo–Clinton run travels to
Whidbey Island. The Pierce County government operates the
Steilacoom–Anderson Island ferry with automobile service to two island communities in southern Puget Sound. The King County Marine Division operates the
King County Water Taxi, a passenger ferry service that connects Downtown Seattle to
West Seattle and Vashon Island. The Vashon Island run was formerly a passenger ferry operated by Washington State Ferries from 1990 until 2006, when the state government cut its funding; the county government later acquired the service under a new ferry district. The passenger-only
Kitsap Fast Ferries system operated by Kitsap Transit connects a terminal near Colman Dock to three terminals on the
Kitsap Peninsula. Kitsap Transit launched the system's first route, Seattle–Bremerton, in 2017 to provide a faster alternative to the existing state ferry run; it expanded using a fleet of
catamarans designed for low
wakes. The agency also runs a passenger-only foot ferry between Bremerton and two terminals in
Port Orchard using the historic
Carlisle II and other boats. The
Port of Everett runs a seasonal passenger ferry between Everett and
Jetty Island in Possession Sound. These services are similar to that of the historic
Mosquito Fleet, a collective name for passenger ferries operated on Puget Sound from the 1880s to 1920s. In addition to public operators, several private ferry and excursion services are based in the Seattle area. The
Victoria Clipper connects Downtown Seattle to
Victoria, British Columbia, via an international passenger ferry.
Argosy Cruises operates sightseeing cruises in Elliott Bay and the Lake Washington Ship Canal; from 2009 to 2021, the company also operated
Tillicum Village, a performance and culinary cruise on
Blake Island. ==Utilities==