First off, if you are looking for a typical ocean cruise, then you won't find it here. No big shows, no casino, no cattle-call port calls. Instead you will enjoy an intimate ship setting that is only available twice each year — between semesters (two and three-week voyages).
Because of the need to position the ship for the next Semester @ Sea world voyage the itineraries are usually Caribbean, Amazon River and Panama Canal passages — a blend of popular port calls and out of the way stops (Nicaragua, Honduras, Trinidad, etc.).
What can you expect? Unique itineraries (smaller ship, very fast), university professors who have sailed on Semester @ Sea voyages who give a series of lectures on the ports you will be visiting (no shop here, shop there chit chat) and if you have questions that go beyond the lecture they will gladly go the extra mile in helping you to understand the history, culture and unique points of interest associated with the ports of call. The professors on board are invited based upon their expertise and the itinerary of each voyage.
There is always plenty of things to do. A university library, free WiFi and internet, movies in the room, lots of decks space. Suggested port trips or do it yourself. Make an Enrichment Voyage part of your cruising experience.