For all of the scuba diving lovers out there, we have to be honest. There really isn't much here for you. The overwhelming majority of Slovenia is land-locked and, while there are some great lakes like Bled and Bohinj, there's little to match the biodiversity of the ocean. And that's why, if you want to dive, you head to Piran.
Located on a tiny peninsula on about 10 miles of coastline between Italy and Croatia, Piran is your Slovenian host on the Adriatic and proves to be the best jumping off point for some of the best reef and wreck dives in this part of the world. Fiesa Reef and Punta Reef are premiere dive opportunities if what you'd like is marine variety at depths up to 70 feet. Expect octopus, conger eels, seahorses, squid, lobster and more at visibility levels that range anywhere from 10-50 feet depending on water conditions. There are a handful of wreck dives that explore what remain of WWII boats, including Kec (a military transport ship) and Maona Rossa (a cargo barge).
The biggest dive center is SUB-NET, located right on the beach. Dives come pretty cheap compared to what you may expect, particularly if you have your own equipment. See their site in our links section for more.