Because cruises are often international, a passport is more than likely required, along with any visas that may be required to enter a port of call. Don't forget cruise documents! In some cases, a ship may require immunization records as well.
Depending on how you handle your money, you'll want some combination of traveler's checks, ATM cards, credit cards or cash. Medical insurance cards, traveler's insurance cards (if you have them) and auto insurance cards for renting cars can also be useful. You may want to bring a driver's license; consider getting an international driver's license, which can be obtained from AAA for a nominal fee. Also consider bringing prepaid international phone cards for calling home.
On a four-day cruise, usually one night will be a formal dining night. Bring at least one outfit appropriate for the occasion. For men, this is usually a suit, a blazer and slacks or, if you want to go all-out, a tuxedo. Women can usually choose a cocktail dress, suit or a long evening dress.
Otherwise, casual clothing will do for almost everything else. Depending on the destination and time of year, lightweight clothing may be best, including shorts, t-shirts, casual button-downs and light blouses. Also consider some of the activities you may choose. Most ships have gyms, spas, swimming pools and jacuzzis, and casinos. Sportswear and swimsuits are likely to come in handy.
Evenings--and sometimes even days--may get cool or even cold. It may be wise to bring a sweatshirt, sweater, lightweight jacket or even a solid all-weather jacket or coat.
Make sure to pack appropriate clothing for ports of call, including light cottons and good walking shoes for tropical destinations or warmer, more outdoorsy choices for Alaska.
Think carefully about what you will want or need. While clothing may be for sale on the ship or at a port of call, it is likely to cost significantly more than it would at home.
For those needing prescription medications, remembering to pack them is vital. Getting prescription medications and refills on the ship or overseas can be difficult and costly. Also, toiletries purchased on a ship are usually expensive and not always your normal brand, so bring yours. Things like over-the-counter medications, hand and body lotions, sunscreen and other personal products are important. Don't forget glasses, contacts and sunglasses as needed.
Consider things like electrical adapters, guide books, phrase books and currency conversion guides, which may be useful tools for on-shore excursions or for your time in a port of call.
