First timer but my understanding is that there are several character opps throughout the cruise and times and locations are in the day's personal navigator. As far as official M&G's, the only available time slots for the Princess Meet and Greet is on our Nassau day at 9:00 or 9:30, and Frozen M&G was that day as well. However the Frozen M&G was also available on sea day at various times between 9:00am and 12:00pm. Very glad we can now book these ahead of time rather than having to rush to guest services right after embarking.