Ships sail under a flag, but what does it mean in practice ?

Under international law, flag states exercise jurisdiction over their vessels and ensure that ships are properly equipped, crews are trained, and masters comply with their obligations, including assisting persons in distress at sea. At sea, roles are shared between shipmasters, coastal states coordinating rescue, and states working together on disembarkation. Flag states are not part of the rescue coordination system and do not have a specific role in determining where rescued persons are disembarked.