Lošinj is an island in the Northern Adriatic. It’s a popular visitor destination for its abundant sunshine, small Venetian fishing villages, cycling/walking paths, and hiking in the interior. It’s reachable by car from the island of Cres or by ferry from Rijeka & numerous other spots. (Access Information)
The best places to run on Lošinj are extensive waterfront promenades in the two main settlements of Mali Lošinj and Veli Lošinj. There’s also excellent trail running on the 220km of hiking trails the hilly interior — the Čikat Bay area is ringed by pine forests, while much of the rest of the island is more open terrain. The main road, Rujnica ul., runs along the water headed north, but has no shoulder and is not safe for running.
Note that Lošinj’s weather in summer can be quite hot and humid.