Here's an interesting update for a cruise passenger initiative from the Port of Seattle's Port Valet program.
Sail from Seattle with participating cruise lines and, if you're flying home afterward with one of the partner airlines, you can apply onboard for the free Port Valet service which will secure your luggage and send it on to the airport direct from the cruise!
That means more time to explore Seattle without having to worry about your bulkier bags.
As I understand the program, you'll have forms to fill out in your cabin once you embark and that you'll need to submit them to your cruise concierge team during the first day or so. Don't delay, you risk missing out!
Once you're successful in applying for their program, you should receive special luggage tags and your boarding passes from the cruise staff the night before disembarkation.
That means you leave your luggage outside your cabin as is the normal procedure prior to disembarkation, but you'll wave "bye" to your bags until after your flight - the cruise port will have them securely transported and checked with your airline.
You get to explore the city, then skip the baggage check-in lines at Seattle Tacoma International Airport because your bags will already be checked through to your final destination!
It even comes with access to the bag-tracking page on Port Valet's website.