We’ve gone to Yuan Spa in Bellevue and Q Spa in Lynnwood. Both are co-ed but I prefer Q Spa since they have dedicated male-only and female-only spaces where you can be nude while Yuan only has co-ed spaces that require a bathing suit. Q Spa also has an in-house restaurant which is divine. Q Spa is great to go with a partner while I’d go to Olympus if I’m solo or with some girlfriends.
Olympus in Lynnwood is the best. Hands down. Women only. Be comfortable in sporting your birthday suit for the day and in spending a long time relaxing there! Restaurant is on site, so you actually never have to leave. Book the scrub AND the moisture wrap, it's the best experience and worth the drive and $$$.
So my mother (also being Korean) wanted to check out Palace Spa in Federal Way - so that's where we went. Scrub and the works. It's also right by Heart, so picked up groceries for the weekend while there. Jenny is the scrub specialist to see, and the Emerald Package is definitely the one to get (scrub and moisturizing). I'd go back again for the convenience factor. It's also co-ed - not my favorite part of it.
I'll have to check out Q Spa.
And when I'm up for the hour drive up to Lynnwood, I'll go back to Olympus - I agree, that's the favorite around here still.
In the NYC region, it's SPA CASTLE!!!!!!! The best I've ever been to if anyone's over on the east coast for travels or the holidays. :)