You sign up once you've boarded, at Guest Services on Deck 3. Don't wait too long once you're on the ship, as space is limited.
You'll meet in one of the lounges at 8:00 AM the morning the ship reaches Castaway Cay. This is to check off runners who have registered, pick up your race bib and safety pins and get instructions and an overview of the course. Runners will be the 1st to get off the ship, around 8:30 AM. You'll then walk over to the post office to wait to be taken to the starting point. There's a spot to drop off a bag, but we just return to our stateroom to shower and grab a bite to eat. Starting time is around 9:00 AM. Make sure you plan on something to hold your Key to the World card, so you can get off & back on the ship. A lanyard around your neck isn't going to work, trust me.
Warning: no matter what time of year you run, wear race clothes for very warm...make that hot...weather. Wear a visor and sunglasses, and sunscreen. There are two water stations along the course, but the island has cold water dispensers with paper cups all over the island and you'll pass several along the course. Important in that part in the loop, as the hedges block any breeze. I stop, get a cup, dump it over my head, grab another to drink.
At the finish line, you'll get your medal. It's rubber, like the old WDW 5k ones. If you want a Castaway Cay 5k tshirt, they are available only on the island, at one of the two shops.
