Elliott Bay Book Company
1521 10th Ave Seattle, WA 98122 United States, Seattle , WA
100% positive
Directions: Go into the bookstore, take a right, walk towards the back and take another right into the internal coffee shop. Towards the back of the coffee shop on the right are two gender neutral bathroom doors. They need a key which is hanging on the counter but since it's frequently busy you'll generally just have to wait in line outside the bathroom for the key.
Comments: Technically you need to be a paying customer but no one will stop you from grabbing a key or waiting in line.