The ship is the Carnival Splendor, which had a fire in the engine room in 2010, stranding passengers off the coast of San Diego.
In this incident, the passengers were taking a tour on land Thursday, when they were robbed of their passports and valuables. No one was hurt.
The cruise line said it's working with guests to reimburse them for lost valuables and assist with lost passports.
Just two weeks ago the U.S. State Department issued a travel warning to avoid unnecessary travel to 14 Mexican states because of increased violence.