You can buy a bottle of wine onboard from any bar and bring it to your cabin or purchase wine in advance via www.rccl.com
and have the bottle delivered to your cabin on the first day of the cruise. RCL policy does not allow passengers to bring their own booze onboard the ship; this includes wine. RCL has a wine package, which basically allows you to "pre-purchase" so many wines throughout the duration of your cruise. The wine packages are normally sold within the dining room. Be careful though, once you "buy the package" you own those bottles, even if you don't finish them by the end of the trip - no refunds. You can always ask them to bring to your cabin so you can enjoy them outside the dinning room. As an example, on my last cruise, I met a young lady who had two bottles still in her package by the last day of the cruise; they simiple gave her both bottles and she drank them by the pool and elsewhere onboard.