American Airlines has round-trip flights from San Antonio or Austin (SAT/AUS) to Grand Cayman (GCM) for $337-$340 with a connection. $120/$210 each-way. Flights depart Dec 17, 18, 19. Flights return Dec 19-27. Origin/Destination reversible.
Note: Carry-on bag is allowed for free, but a checked bag will cost +$30 each-way. Upgrades into “Regular Economy” are available for +$30 each-way.