The new term is "elegant" nights and there are two of them, the first is the captains night and is usually held the first full sea day. the other is typicially the first full sea day of the return trip. Last year we arrived in San Juan almost an hour early. and if you are booking the excursion through carnival then you will be able to do it even if we are slightly late. Upon sail away from San Juan there will be a deck party with a mexican buffet and music and dancing overall a really good time starts about 12:30am and lasts a few hours.