Welcome aboard, William! Congratulations on booking your sailing on the Disney Dream for this summer! Your granddaughter is going to have the time of her life on the cruise!
Technically, she will only need her birth certificate as proof of identification, however if you can get her a passport, it wouldn't hurt. Over on Disney Cruise Line's website, you can read about the
benefits of having a passport as opposed to just the birth certificate. However, if you choose to forgo the passport, you should be just fine traveling with your granddaughter's birth certificate on most sailings. Look at DCL's site for the
travel documentation required for each itinerary for specifics.
Since you mentioned that your granddaughter is two, you should also be sure to look into scheduling a couple of hours for her in the
It's A Small World nursery onboard so the adults can sneak away for a dinner at the Adult Exclusive Palo or Remy, or just some adult entertainment or relaxing by the Quiet Cove adults-only pool. The nursery time does cost a bit extra and books quickly, so be sure to reserve a time before you board.
Have fun planning your multi-generational cruise! We've sailed with grandparents a few times and the kids have really enjoyed those special trips! Please let me know if I can help you with anything else, William!