Besides of scuba-diving you can also try climbing. But you should know that the peaks in Croatia are not higher than 2,000 meters, they are among the most beautiful in the world. The most of Croatian mountains belong to the Dinaric Mountain Range. The Dinaric Mountains are characteristic of the rocky relief, while the inland mountains (in the past they were the islands of the Pannonian Sea ) are somewhat lower, more wooded, older in origin and generally more accessible.

People most often climb the mountain Medvednica and the mountain range of Samobor. Because Croatian mountains are easy to climb and have a large number of attractive destinations, the number of opportunities and combinations is unlimited.

So now examples which show where you should go/what you have to see  :

Dinara - 1831 m
Kamesnica - 1809 m
Biokovo - 1762 m (Sv. Jure)
Velebit - 1758 m (Vaganski Vrh)

Lička Plješevica - 1657 m (Ozeblin)
Velika Kapela - 1534 m (Bjelolasica)
Risnjak in Gorski kotar - 1528 m
Svilaja, Dalmatia - 1508 m
Snježnik, Gorski kotar - 1505 m
Učka - 1401 m (Vojak)

Pannonic - Peripannonic regions:

Žumberačka Gora - 1178 m (Sveta Gora)
Ivančica - 1060 m
Medvednica - 1033 m (Sljeme)
Psunj - 985 m (Brezovo Polje)
Papuk - 954 m
Samoborsko Gorje - 879 m (Japetic)
Krndija - 792 m (Kapavac)

Islands:

Brač - 778 m (Vidova Gora)
Cres - 650 m (Gorica)
Hvar - 626 m (St. Nikola)
Lošinj - 588 m (Osorščica)
Vis - 587 m (Hum)
Krk - 569 m (Obzova)
Korčula - 568 m (Klupca)
Mljet - 514 m (Velji Grad)
Lastovo - 417 m (Hum)
Rab - 403 m (Kamenjak)