Once again...an important reminder.
Yes, yes, it is true, most crew members, probably all crew members, are required to have their STCW-95 Certification prior to boarding a cruise ship and assuming your duties.
In the US it is called STCW-95; in Canada, the equivalent is called BST (Basic Safety Training). In whichever country you take this training, make sure it is equivalent to the US Coast Guard STCW-95 - if you are not sure, contact the Coast Guard in your country and just ask them. Also, make sure the cruise line and/or hiring agent, clarifies what you need before you spend hundreds of dollars!