In the photo, the woman can be seen standing dangerously on top of the railing of her room's balcony.
It was on her trip aboard Royal Caribbean's Allure of the Seas this week, as it was headed toward Haiti.
A fellow passenger snapped this picture, and thinking she was possibly going to jump, he alerted the crew.
The woman was identified and later removed from the ship when it reached Jamaica.
Royal Caribbean in a statement said it does not permit any such reckless and dangerous actions, for guests' own safety.
As a result, the cruise line said the woman and her companion are banned for life from any of its future trips.