There are two issues with a defendant leaving the state or even the country while out on a bail bond. The first is with the presiding court. The defendant can not leave if the court has prohibited them from traveling outside the state or country. All defendants should confirm the court has not placed this restriction on them before leaving. In addition, the bail bondsman must also approve of interstate or international travel by the defendant. If either of those two parties doesn't authorize such travel the defendant is not allowed to go. If the defendant goes anyway, they are subject to arrest and possible additional charges.