Regional Transportation District operates a bus from Boulder to Keystone hourly. Tickets cost $9 and the journey takes 1 h 7 min. Summit Express also services this route 5 times a day.
How to get from Boulder to Keystone
From Broadway & Euclid Ave bus to Denver International Airport then bus to Keystone Resort. 4 h 7 min $128. From Boulder drive to Keystone. 1 h 36 min $10. From Downtown Boulder Station Gate 2 bus to Denver Airport then shuttle to Keystone. 4 h 7 min $74.