The average bus between SeaTac and Castle Rock takes 15h 48m and the fastest bus takes 15h 46m. There is at least one bus per day from SeaTac to Castle Rock. The journey time may be longer on weekends and holidays; use the search form on this page to search for a specific travel date.
Buses run once daily between SeaTac and Castle Rock. The earliest departure is at 2:45 PM in the afternoon, and the last departure from SeaTac is at 4:50 PM which arrives into Castle Rock at 8:36 AM. All services require a transfer at Olympia and take an average of 15h 48m. The schedules shown below are for the next available departures.
Arrives next day


15h 51m • 2 changes
Arrives next day


15h 46m • 2 changes
Arrives next day


15h 51m • 2 changes
Arrives next day


15h 46m • 2 changes
Want to know about travelling from SeaTac to Castle Rock? We have put together a list of the most frequently asked questions from our users such as: What is the cheapest mode of transport? What is the quickest option? How much do tickets usually cost? and many more.
No, there is no direct bus from SeaTac to Castle Rock. However, there are services departing from SeaTac station and arriving at Castle Rock station via Olympia. The journey, including transfers, takes approximately 15h 48m.
SeaTac to Castle Rock bus services, operated by Greyhound USA, depart from Seattle Tacoma Intl Airport station.
SeaTac to Castle Rock bus services, operated by Greyhound USA, arrive at Castle Rock Park and Ride station.
The distance between SeaTac and Castle Rock is 138.7 km. The road distance is 180 km.
You can take a bus from Seattle Tacoma Intl Airport to Castle Rock Park and Ride via Olympia, Olympia Transit Center - 280 Washington St NE, and Mellen Street e-Transit Station - 1401 Mellen St. in around 4h 44m.