Update (6:31pm ET, Jan. 17): The following dates are now sold-out: March 19

Spend spring break on a five-night Caribbean cruise for $399 per person. This deal knocks $250 off current rates and comes with a 15% discount on select shore excursions.

Sail roundtrip from Fort Lauderdale on the  Royal Caribbean's Navigator of the Seas, named one of the top mega-ships in the world by Conde Nast Traveler last year. It has a rock-climbing wall, ice-skating rink, water park and mini-golf course on board.

The departure date determines the itinerary:

• March 26; April 9, 23 departures for stops in Grand Cayman and Cozumel
• April 4 departure for stops in Labadee, Haiti, and Falmouth, Jamaica
• $25 onboard credit per cabin (March 26 and April 4 departures only) 

Or sail roundtrip from Tampa on Royal Caribbean's Radiance of the Seas. Depart March 5, 19 and April 11 for stops in Cozumel and Costa Maya, Mexico 

Book by Jan. 18.

Travelzoo Tip: Book this cruise with any American Express card and get an additional $50 in onboard credit at a minimum. The credits increase with the total booking price.