I've done this excursion 3 times on NCL our tour started at 1:00 pm from the docked ship with the cruise ship leaving port at 1:30, that gave us about 2.5-3 hours at the glacier before the cruise ship showed up where we got back on the ship for the cruise out of the Fjord. This can only be booked through the cruise line. This is by far my favorite Alaskan Excursion!