I'm just looking through my Navigators from our 2018 Med cruise. Looks like mid-afternoon a few characters met. Jake was the earliest at 2:30 and 3:30, but Goofy and Mickey didn't start until 4:45 and 5:45 respectively on our Naples day.
In Livorno we had Sofia at 2:45 and Pluto at 3:45, Hook and Smee at 4:45 and then things really take off from there.
In Genoa, things started slightly earlier with more of the main characters with Pluto at 2:30, Goofy at 3:00 and Daisy at 3:30.
In Villefranche it was actually slightly earlier as we got Chip and Dale at 2:15 up on the pool deck in the Gazebo. Several other characters met there through the rest of the afternoon.
In Marseilles, Mickey and Minnie actually met in the morning at 8:45, 9:15 and 9:45 before taking a break and then characters started again at 4:30 with Daisy.
I don't know how things are going down since the restart and it's hard when we don't have paper navigators people have scanned in for reference. I kept all mine from past cruises that had them, but now that it's in the app, it's hard to know.
Have a great cruise. We loved being in the Med. We actually weren't on the ship overly much during the day. I hope that's the case for you as well because there is so much to explore!
