"We are so happy to offer St. Louis-area residents this new, nonstop service to Sarasota/Bradenton this winter", said Drew Wells, Allegiant vice president of planning and revenue.
As part of the announcement, Allegiant said it was offering one-way fares online starting at $69.
The new seasonal route will operate twice weekly.
"We are thrilled to add the sixth dot to our route map with Allegiant", said Mike Daigle, South Bend International Airport CEO and executive director.
Passenger traffic at Sarasota-Bradenton set an all-time record for the month of June with 147,615 passengers traveling through the airport, and year-to-date passenger numbers are up almost 40 percent, making Sarasota-Bradenton the second-fastest growing airport in the country.
A new route to Florida is coming to MidAmerica Airport this fall. With the additional two flights each week, Allegiant will fly to five cities from Flint.