You didn't mention what resort you are going to. But I can say that no matter which resort you are going to, there will be a party when you arrive. Make sure to either wear your party clothes (if not traveling too far) or pack them in your carry-on (along with swim suits for the morning after). That way, if something happens to your luggage, it won't interfere with your having the best NYE ever.
At CSA the kick-off is at the piano bar at 5 or 5:30 and that is followed by the (Amazing) cocktail party at around 6:30 (check the schedule on arrival to be sure). I recommend heading over to the party as soon as you get checked in. Also, for dinner, there are generally two choices and reservations are taken (in person) for seating. I am not sure how the concierge handles people arriving on the night of the event, but I am sure they will be expecting you. Perhaps you might want to call or email to see if they will let you reserve your table ahead since you will be arriving just barely before seating.
Hi Bob and Bernadette. Ultimate traditionally has a short sing along to kick things off and begin welcoming in the new year. Most of the piano bar regulars are in attendance. There are some Scotts and others from the UK who come most years, so we ring in their new year with them at 6 p.m. Jamaica time (midnight in the UK). It is fun to wish everyone a happy new year in this more intimate setting before the evenings major festivities begin. It is short and sweet and then we enter the main cocktail party together when it opens up (it's right in the next room). If you like sing-alongs, you should come join us.