It is more than likely that you will fly to Pula, which is the main airport in the region – see our Getting to Istria page for details of flights to Pula from Europe. From the airport, there are public shuttle buses that operate to Poreč – see the timetable on the FILS website. For more options, you could also be transferred to the main bus terminal in Pula (either by taxi or transfer bus) and then take another bus from there to Poreč.
Alternatively, you may like to arrange a private transfer from Pula Airport direct to Poreč, which may not be too expensive if there are a number of you travelling together. Pula Airport is about 34 miles/55km south of Poreč. You could also fly to Trieste and then get a bus to Poreč, or fly to Venice and get a catamaran across the Adriatic. See our guides on travelling from Trieste and Venice to Croatia for details of bus and catamaran routes.
For more information please check the official Poreč website.