Yes, all private yachts—both domestic and foreign-flagged—must go through customs and immigration clearance when traveling between countries. When a yacht enters a foreign port, the "skipper" or master must report the arrival to the local customs authority (such as CBP in the USA) usually within 24 hours. Every person on board must present a valid passport and clear immigration, even if they don't plan to step off the vessel. You must also declare any restricted goods, such as alcohol, tobacco, or firearms. In 2026, many countries require pre-notification (APIS) via email or an app at least 48 hours before arrival. Failure to report can result in heavy fines, confiscation of the vessel, or even the arrest of the crew, as yachts are often scrutinized for potential drug trafficking.