Arrival in Orebic -
Coming by ship ?
You can use ferry and ship lines - during the summer several shipping lines connect Split & Rijeka with Korcula (Jadrolinija) and Korcula with italian harbors (Blue line & SEM maritime company). From Korcula - you can easily cross to Orebic using very frequent passenger ship or ferry line.
Coming to Orebic by plane ?
Nearest airports to Peljesac & Orebic are those in Dubrovnik (about 120 km) and Split (about 230 km) - which are well connected with most of the major European airports.