The Elliott Bay Water Taxi started service in 1997 as a pilot project to give commuters an alternative to the congested West Seattle Bridge and Highway 99.

[15] King County Ferry District leased the catamaran MV Melissa Ann from Four Seasons Marine Services to operate the Vashon Island route.

In addition to being more stable, the catamaran was also faster than the ships operated by the Washington State Ferries reducing travel time from 30 to 22 minutes.

[15] In April 2010, the West Seattle route began operating year-round service from a newly rebuilt dock at Seacrest Park that allowed for wheelchair access.

[16] At the same time the West Seattle route started operating with the catamaran MV Rachel Marie (a sister ship of the Melissa Ann), also leased from Four Seasons Marine Services.

In 2014, the district received federal grants that allowed it to purchase two ships specifically designed for the needs of the King County Water Taxi.

[21] The addition of the Sally Fox to the fleet allowed the leased Rachel Marie to be returned to Four Seasons Marine Services in December 2014.

The second new vessel, the MV Doc Maynard was delivered in October 2015 and after modifications were made to the dock at Seacrest Park, the new ship began service on the West Seattle/Downtown Seattle route on January 7, 2016.

[24] On November 2, 2023, the captain and crew of the Doc Maynard spotted a runaway container ship that was floating adrift towards the Seattle Aquarium.

In September 2021, due to construction on the West Seattle High Bridge, service was expanded to include midday sailings as part of a pilot program.

[30][31] King County Metro operates two shuttle bus routes that take passengers to and from the dock at Seacrest Park.

[32] The primary ferry for the route is MV Sally Fox, which carries an average of 400 passengers per day in each direction and was named for a Vashon activist.

[36] Connecting services include King County Metro bus routes 118 and 119, which traverse Vashon and Maury islands.

[36][38] As of September 1, 2022, the one-way fares for the King County Water Taxi are:[39][40] Crew members accept ORCA with a hand-held card reader, or passengers can pay with cash (no change given) or a pre-purchased tickets at the farebox on the vessel.