Welcome back, J! Guests who have sailed with Disney Cruise Line at least one time before are automatically members of the
Castaway Club. Your number is assigned, and it sounds like you've received your number, which means you must have sailed with Disney before.
When you book future cruises, this number is associated with your reservation, letting Disney Cruise Line know that you've sailed with them in the past. As a guest who has sailed 1-4 times with Disney before, you'll be a Silver Castaway Club Member. After five cruises, you'll become Gold, and then Platinum after 10. The perks increase with each level of membership.
The perks begin before you even set sail. As a Silver member, you can begin booking all those fun extras like Port Adventures before first time guests. At 90 days prior to sailing, your
online check-in begins. Take advantage of that early time to book Port Adventures, Adult Exclusive Dining, Spa Treatments and more before the first time guests log in. You'll have better chances of getting the exact reservations you'd like.
As you arrive at the port, you'll notice your Silver Castaway Club line, allowing you to check in a bit faster than waiting in line with the folks who are sailing for the first time. You'll receive a silver lanyard to wear with your Key To The World Card. When you arrive at your stateroom the first day, you'll have a special Castaway Club gift waiting for you! There are many other perks for Castaway Club members, so be sure to read about those on the Castaway Club page.
I hope those details help as you continue planning your cruise, J! Happy sailing!