For travel over the Labor Day holiday, fly nonstop from San Francisco to Seattle for $307 roundtrip on Delta.
Searching Delta, I found seats departing SFO on Friday, August 30, returning from SEA on Tuesday, September 3.
This fare includes a carry-on bag plus one small personal item. A checked bag costs $30 each way.
This ticket includes seat selection which you can select when booking.
Lower fares are available in basic economy, though advanced seat selection would not be included.
Check out other Labor Day finds here.
Need a room in Seattle? Here's what's available for the above dates on Hotelwatchdog.