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Tickets went on sale at midnight for the new routes: from Atlanta to Aruba and Montego Bay, Jamaica; from Orlando, Fla., to Jamaica and Aruba; and from Baltimore-Washington International Airport to Aruba, Jamaica and the Bahamas.
Currently the company is already flying international flights via its wholly owned subsidiary AirTran Airways to Nassau and Montego Bay and to Cancun, Los Cabos and Mexico City in Mexico and to Punta Cana in the Dominican Republic. Those are all expected to convert to Southwest routes by the end of 2014 as the integration of the two airlines completes. Kelly said more international routes could be added as soon as 2015.
"We're starting out conservatively," said Kelly, who earlier noted that Southwest launched 43 years ago with only three routes, all within Texas.
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"It's a big component of our growth strategy," Bob Jordan, executive vice president and chief commercial officer and president for AirTran, said of the new international routes. He said in coming years there are opportunities to add about 70 to 80 planes on new international routes, mainly to locations south of the United States.
"Most of these are overfared. Some of these are two to three times what Southwest would charge," Jordan said.
The company's network route map covers 96 destinations in six countries.
The Southwest impact on international fares remains to be seen. "I think it's historic for the airline, but I don't think consumers will think it's historic," said Jay Sorensen, president of IdeaWorks, an airline research firm.
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The reason, he said, is because the concept of "low-fare airlines" has changed to the point where only Spirit and Allegiant moving into a route would cause other airlines to drop prices, Sorensen said.
—By CNBC's Amy Langfield. Follow her on Twitter at
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