There are several ways of reaching the island of Losinj.
To reach the island by car from Croatia, first you need to go to the island of Cres given that Cres and Lošinj are connected.
There are also several bus lines connecting Zagreb and Rijeka with the island of Lošinj. The average ticket price is around 20€.
FERRY TO LOŠINJ
The ferry transport to the island is operated by the Croatian company Jadrolinija d.d.
The islands of Cres and Lošinj are connected to the mainland by ferry lines Merag (Cres) – Valbiska (Krk) and Porozina (Cres) – Brestova (Istra), and Lošinj is also by ferry and catamaran line connected to Zadar and Pula. More information about timetables and prices are listed on https://www.jadrolinija.hr/en.
More information can be found on https://www.ferrycroatia.com/en/island-losinj/.
GETTING TO LOŠINJ FROM RIJEKA AIRPORT
If you fly first to somewhere else in Croatia, then the nearest large airport is Rijeka Airport on Krk. From there, you can take a direct bus from Omišalj to Lošinj.