Kostrena is situated on the Kvarner Bay, east of Rijeka and has a population of about 4.000. It has nice beaches, made of pebbles or concrete, which is quite common in that area. The most popular diving center is DC Kostrena.
How to get there
By plane to the International Airport of Rijeka (RJK) on the island of Krk. The airport from the 1970ies is a must see as it appeared to me more as a regional airport then a previously intercontinental airport. It is very cute. From the airport to Rijeka it takes about 30 minutes (~30km distance). A taxi from Rijeka to Kostrena costs around 60 Kuna (~8 EUR).
Diving Center Kostrena
The DC Kostrena with direct access to the sea is one of the oldest diving centers in Croatia and consists of a quite big villa containing apartments, the diving center itself and a restaurant with a beach bar. It can easily be aproached by car with parking lots available right at the diving center, only about 20m to the seashore. The diving spot in front of the center is very nice, as it has enough shallow water for beginners with depths between 5 to 10m but also "the wall" which allows straight descents to 35-40m for experienced divers. The area around the center is protected since 1962 and the reef offers quite a variety of sea plants, corals and fish.