Legal Question in Family Law in Florida

generally no, she does not need permission for a short cruise unless the court order requires it, which is unlikely. It may be easier to just have dad sign a permission slip than explain things to the cruise line.

When traveling to another country, U.S. law and the law of many--maybe even most--foreign countries requires that the traveling parent carry a letter from the other parent allowing permission for the travel. The law is based on an international treaty intended to prevent international kidnappings. Airlines and cruise ships often wisely require these letters as well. Some countries offer exceptions, such as wheer the other parent is deceased (obviously) or where a parent has "sole custody." It does not appear that your sister has sole custody, so she will need a letter from the father. Some countries require specific wording in the letter (the U.S. does not), and you can check with the cruise line or the consulate of the foreign country for help with the letter. A lawyer may be able to help, also. If the father refuses to sign, you may file a motion in family court to obtain permission from the judge. The motion will require a hearing, and your sister will have to formally notify the father of the hearing date. Again, this is something a lawyer can help with.