Seaman’s books are useful for logging sea service, seaman’s fares (extra luggage on flights that accommodate seafarers), as a second form of identification, visa applications – for those that need visas… most consulates will ask for you to show your seaman’s book.

You can either get a seaman’s book from your country of residence (if that country is able to provide seaman’s books), OR you can apply through your current boats flag state – that means that you have to be employed on a vessel in order to apply through their flag state… you can’t choose any seaman’s book.