You should contact Norwegian Cruise Line directly for an answer for this at 1-866-234-7350. Different cruise lines have different regulations and so do different countries.
The information above does not sound exactly accurate for European cruises. It does have some merit when referencing cruising from a US port due to the
Passenger Vessel Services Act of 1886 also knows as the PVSA or "Jones Act".
Keep in mind cruise lines are not in the business of holding people hostage on the ship. If you want to leave and not return, the cruise line technically can’t stop you, no matter what they say. That being said, it could also cost you in fees and fines from the cruise line and embarkation/debarkation countries depending on the situation. Then there is the possibility of being banned from using that cruise line again.
In any event, always be sure the cruise line knows your plans. Otherwise, they may believe they have a missing passenger. You will also need to inquire about immigration status in the foreign port. Even though there should be a record of your travel to the foreign country (which you should carry with you at all times after disembarking), you won’t have a passport stamp to prove your entry. This could make for a tougher time when exiting the country.
