yes there is a bus that runs to san an via the bay.see link for map of hotels is passes.around 3 euro last time i looked..

http://www.ibizamaps.net/images/pdf/ibizabus-timetables.pdf#page=9

as you walk outside in fresh air of airport.turn right busstop is there.15 to 20 mins with drop offs.or you might ask at taxi rank if someone might share a cab with you.depends how many of you there is.number 9 bus your looking at