Check-in will always be opened 45 days out from the sailing. That being said, if you're like me, you'll wait a couple days until the actual sailing to complete the online check-in process. Don't wait! I can't emphasize enough the vitality of checking early because it allows to utilize the time to get any travel related issues sorted out, such as a passport that will expire soon. I hope you found this information valuable, have a great cruise!