Your first time onboard
Once hired you will need to get all your visas for your travel and a medical. Usually you will be advised by the hiring agent which are the approved medical facilities you can obtain your medical from. You may be asked to attend a training school prior to joining the ship, which will take care of some important safety and customer oriented training that is mandatory for the Hotel personnel to work onboard. If you are a Marine officer (Navigators, Engineers, etc) you will obviously need all your licenses and certificates for company required training.
When all this is nicely prepared, you will need to start packing. To be able to figure out what to bring onboard, you need to be aware of where the ship you are joining is sailing and what type of climate and season you will face. You also have to be aware that the airlines nowadays charge for luggage, so get familiar with the airlines baggage policy ahead of time, to avoid disappointment when asked to pay for a few extra kilos.
Most likely you will be on one ship for the entire contract, but it is not unusual for a company to transfer you mid contract to fill a business need. So, if you have only brought summer clothes for the Caribbean and you get sent to Alaska for 3 months mid contract, you will most definitely need warmer clothes. You may be better off bringing a small jacket just in case, to avoid buying an expensive cold weather gear once onboard.
When on the ship, you may not have a great opportunity to wear formal clothes, unless you have a position that allows you to be in a guest area and as such, you may be allowed to wear your own clothes, however when this is the case you will be asked to dress nicely. Casual clothes and a nice pair of pants and a shirt may be sufficient if you don’t plan on being in a guest area regularly. Swim suit is always a must and workout clothes, as most crew members like to enjoy the gym, riding a bike and practicing other sports when not at work.
Inquire about what shoes you will be allowed to wear with your uniform (which will be given to you once onboard) and try to get comfortable shoes with a good grip to avoid an accident like slip and fall. Bring a small amount of toiletries and necessities, as you will be able to get more once onboard. Most of the ports have shops for the crew and you can get these inexpensively in several places.
Bring your phone, tablet or/and laptop (you will need it to converse with your family and friends and watch movies when in your cabin). Most cruise lines have equipped the crew rooms with TVs, DVD players and fridges, but you may want to watch movies or listen to some music on your laptop as well. The crew cabins are equipped with small safes where you can keep your valuables, however don’t go overboard bringing expensive jewelry or watches.
Final word of advise- try to pack lightly, as while traveling you will acquire more stuff- gifts, souvenirs, etc and you will need to have this extra room in your suitcase, to avoid buying an extra bag. Do not forget to bring $100 with you at least, to cover travel expenses and allow you to have some money until you get your first pay. Get a nice haircut before joining and purchase any medication you may need for the duration of the entire contract, as the medical facility onboard may not have it.