Ahoy there, Samantha,
Welcome aboard planDisney! How fun to sail away with your sister and her husband, especially for their first Disney Cruise Line vacation!
Since your
Castaway Club status will allow you to complete your Online Check-In and select a Port Arrival Time earlier than your sister, you will likely have an earlier boarding time than her. Your best bet for booking the same time is to select a later time from those offered to you when you check in and hopefully, her arrival time will line up since you can always wait to arrive with her, but she can't arrive early. If not, once she completes her online check-in and selects a time, you can modify yours to the time she selected by navigating back to Online Check-in under the
Already Booked tab or Online Check-In in the
Disney Cruise Line Navigator app. Keep in mind that your
port arrival time and your actual boarding time are not the same. You will have to complete an in-person check-in process and then wait for your Boarding Group to be called.
Just a reminder that you will need your original travel documentation and your port arrival form (which can be on your smartphone or printed) when you arrive at the port. You will need to have these items in your carry-on baggage and ready to go once you arrive at the port. Also, think ahead about how you would like your party to be introduced when boarding the ship. One of my favorite moments is when the Crew Member announces our name as we board!
Samantha, I hope this information helps you make your plans. Let us know if you have other questions; we are always happy to help!
Wishing you many magical memories,
Shannon