Sound Transit is studying the following station alternatives in South Lake Union.
- Tunnel Harrison Street Station (associated with the 5th Avenue and Harrison Alternative) (Preferred alternative)
- Tunnel station under Harrison Street between Aurora Avenue North and Dexter Avenue North
- Tunnel Mercer Street Station (associated with the 6th Avenue and Republican Alternative)
- Tunnel station on the north side of Mercer Street between Taylor Avenue North and State Route 99 / Aurora Avenue North