On most every cruise line, you can wear pretty much anything you want during the day, except that you can not wear beachwear into the main dining room at lunch.
For the evenings, however, every cruise line has slightly different ‘suggested’ dress for the evening, which can change daily. If there is something special you need to know about (such as Black and White Ball on Cunard), they will give you the information in your cruise documents so you can be prepared.
Depending on the length of the cruise, there’s usually ALWAYS at least one ‘formal or elegant night,’ but if it is a longer cruise there may be more. Traditionally, Formal is defined as a tuxedo or dark suit for men and an evening gown or cocktail dress for women. Informal is defined as a jacket and slacks for men and a dress or pant suit for women. Resort Casual is defined as ‘dressy casual’ and is the typical ‘dress’ for most dinners other than formal nights.
Norwegian Cruise Line is quite casual, but does have a dress up night, though you can certainly dress up or not. On the other hand, SeaDream’s resort casual requires a bit more fashionable approach. Each cruise line outlines ‘their’ expectation level and is available on their website – you just don’t want to be refused to enter the dining room some night because you were not dressed appropriately (it happened to us one time and was very embarrassing).
That being said, on a cruise ‘Formal or Elegant Night’ is still YOUR interpretation of formal – you can opt for the fanciest, sparkliest gown you own or just what you wear to church on Sunday – both are totally acceptable and you will see the full gamut that night. Again, it’s YOUR interpretation of ‘Elegant night.’
You now have the permission to be comfortable in whatever YOU have selected! Do not be concerned about what others wear or what they might think – you will never see these people again! (But DO walk around – those that are in full dress just LOVE getting those compliments!)
If you absolutely do not want to ‘dress up’ for formal night, you may want to order room service (Some cruise lines adopt the policy that by not dressing up that you ‘ruin it for everyone else’ – my guess is that if you really don’t like to dress up much, that you would not select that kind of a cruise line to begin with!).
Formal night is also the staff photographer’s opportunity to take a ‘formal’ photograph of you and your traveling partner(s). If the last time you had a nice picture taken of you and your spouse was your wedding, this would be a VERY good time to splurge and really take advantage of this opportunity.