There is a good public transport network in Ibiza and buses are a cheap way to get around the island. However, bus frequency drops dramatically over the weekend. Check out timetables at the web site below.
Ibizabus no. 10 leaves Ibiza Airport to the city’s main bus station every half an hour between 07:20 and 22:50, to Ibiza, which is located at the Avenida Isidoro Macabich.