Westlake station consists of two underground side platforms, connected to the surface by entrances and a mezzanine level served by nearby department stores. It is situated between University Street station to the south, and Convention Place station to the north; Convention Place is only served by buses, however, and Capitol Hill station is the next northbound light rail station. The transit tunnel was built in the 1980s and opened for bus-only service on September 15, 1990. The tunnel was closed from 2005 to 2007 for a large renovation to prepare for light rail service, which began on July 18, 2009. Link light rail trains terminated at Westlake until the opening of the University Link Extension in 2016. Trains and buses serve the station twenty hours a day on most days; the headway between light rail trains is six minutes during peak periods, with less frequent service at other times. The tunnel will become train-only by 2019, and a second downtown tunnel is planned to be built in 2030, with a transfer at Westlake station.
Westlake station is located on Pine Street between 3rd and 6th avenues in Downtown Seattle's retail and office district. The station is at the north end of Downtown Seattle, near the Denny Triangle area, and is within walking distance of the Pike Place Market Historic District. According to the Puget Sound Regional Council, the area within 1⁄2 mile (0.8 km) of the station has an estimated population of 15,171 people (in 12,995 total housing units, mostly in multifamily buildings) and approximately 91,055 jobs.