Flights at this price are available on select Tuesdays, Wednesdays, and the occasional Thursday starting in early November through December 13, 2018. Other departure days during the week can also be found in the mid-$300 range if you are looking for a wider travel window. This is a new route starting up from Ft. Lauderdale, so all flight connections will transit via FLL with reasonable layover times.
Searching on JetBlue.com, I could find seats departing PIT on Tuesday, November 6 and returning from GCM on Wednesday, November 14, 2018. Tickets are selling out fast so jump on this deal if you are looking for a quick Caribbean getaway.
We have lots of other deals to the islands today, so make sure to head on over to our Caribbean Flight Deal page for a full list of findings.
If you are looking for that idyllic island hotel by the beach we've got you covered with a few choices from Hotelwatchdog for the dates mentioned above.