How to get from Sorrento to Bari

Take the Curreri bus to the airport in Naples and fly on one of the lo-cost inter EU airlines that you can find on Whichbudget or Skyscanner.com. Be mindful of luggage restrictions.

We, four adults are traveling from Sorrento to Ostuni on Aug. 30. We are staying for 8 nights before heading back to Rome. I am renting a car. I have driven in Italy in the past and feel confident. The trains in this region are not as plentiful and sometimes they are replaced by buses. Also, I understand that car is necessary to get from town to town. Are you planning on staying only in Bari. Perhaps you don't need a car. Check around. I know when I return to Rome I have to take the car to the Bari airport because the rental places are closed in Sundays and close early on Saturday.
Hope this helps. Lorie

From Sorrento take the Circumvesuviana train to Napoli Centrale. Then from Napoli take a Trenitalia train (one train change in Caserta). The travel time from Naples is less than 4 hours. There are no direct flight options from NAP to BRI. You could fly to Rome or London or Paris (or any other EU hubs) from Naples and then from there to Bari, but that would be crazy even to contemplate.

A few years ago, I took the train route Roberto suggests and it worked well. I left Sorrento around noon and was in Bari around 6:00.

Thanks to everyone for responding.