Istria is the largest Croatian, and also Adriatic peninsula. In the north, the Croatian part of Istria (90% of total peninsula territory) ends, bordering with the Republic of Slovenia, while on the east a natural border is the Učka mountain. Istria holds the westernmost point of the Republic of Croatia – cape Lako. Here you can find a variety of geomorphological forms, out of which we can point out three land reliefs: mountainous north with karst features, lower flysch hills in central Istria and low limestone plateau. The main feature of the peninsula is the Mediterranean climate with over 2 000 sunny hours a year, but because of the proximity to the Alps inland climate changes to continental. Peninsula is mostly covered by Mediterranean vegetation like maquis shrubland, but there are also some areas covered by pedunculate oak, which is usually characteristic for continental plateau parts of Croatia. Largest towns are Pula, Rovinj, and Poreč.

Kvarner is the north part of the Adriatic sea between the coasts of Velebit and Istria. In the Kvarner gulf are the two largest Croatian islands – Cres and Krk. The climate is various, Mediterranean with hot summers and mild winters in the coast and on the islands, and a continental climate in the hills and an alpine climate in the higher parts. Highlights of the area are the various plants and wildlife, among which we need to point out endangered species like griffon vulture, dolphins, and bobcat. The largest town is Rijeka, the largest port of Republic of Croatia and important traffic junction which is on the almost same distance from München, Vienna, Budapest, and Bratislava.