Southwest Airlines is making moves in the Caribbean.

The carrier officially launched new daily nonstop service to four Caribbean destinations on Sunday, all out of its growing Caribbean-network hub in Fort Lauderdale.

The carrier has launched daily nonstop service from Fort Lauderdale to Grand Cayman, Cayman Islands; Montego Bay, Jamaica; Belize City, Belize; and Cancun, Mexico.

The Half Moon resort in Montego Bay, Jamaica.

Also Sunday, Southwest launched two other new Caribbean routes: one between Cincinnati and Grand Cayman and the other between Chicago-Midway Airport and San Juan, Puerto Rico.

Old San Juan, Puerto Rico

The new flights are the latest part of a major regional expansion for the low-cost carrier, which earlier this year launched service between Denver and Belize.

Seven Mile Beach, Grand Cayman.

Southwest had already been operating daily flights between Fort Lauderdale and Nassau, Bahamas, along with a number of flights to destinations in Cuba.

Nassau, Bahamas.

The new flights represent the first significant challenge to competitor JetBlue’s fast-growing Caribbean network, as rival American Airlines seems to have slowed its expansion in the Caribbean.

—Alexander Britell