Puerto Rico. Stay at the Hilton caribe as they have their own lagoon and you can swim every day. Lots of pools and grass for little ones. If you get a villa with a kitchen you can save some and make your own breakfast and lunch. Southwest flies non stop and it's less than 4 hrs each way.

We did a Sarasota/Marco Island/Naples trip around New Year's and it was windy, jacket weather on the beach in Sarasota in the early part of the week. Was still good for nature trips inland, walking, tennis, biking, exploring historic sites & shops. Swimsuit weather in Marco Island/Naples later the same week. Especially inland. Leilei area is nice and warm and close to both places as well as the Everglades.

I don't think you can guarantee warm/beach unless you leave the U.S. We went to Cancun for 2 Christmases and it was nice.

I would head for Marco Island. It is further south than Sarasota so somewhat warmer.

For 10 years, my parents lived in Sarasota and each year we spent the week of Xmas there. You can fly direct from national. It is a lovely little city, with plenty of things to do with kids--an aquarium, a "jungle garden," botanical garden, the Ringling Bros. Museum, wonderful Myakka state park, and gorgeous beaches.

I know this is last second, relatively speaking, but DH and I just started kicking around the idea of taking the kids somewhere warm for a few days around Christmas. He actually is advocating for a Disney cruise because DD would be thrilled, but I don't think we have it that together. Any suggestions for (1) warm / beach (2) a direct flight (3) under 1K a night with separate bedrooms for the small ones?