The Dallas-based carrier said Thursday it will operate three daily flights to San Juan, Puerto Rico, from Orlando, Fla., and one from Tampa, Fla.
The routes are currently flown by AirTran Airways, which Dallas-based Southwest bought last year.
The Southwest flights will start April 14. The airline touted a special fare of $99 each way for tickets purchased by next Tuesday for travel between April 15 and May 23 except Fridays and Sundays.
AirTran will still fly to San Juan from Baltimore, Atlanta and Fort Lauderdale, Fla. Southwest said it was determining when to switch those flights to the Southwest name.