Croatian for "long island", Dugi otok is just that; 45 km long and only 5 km wide. Just off the coast of Zadar, it has the usual qualities of an island in the Adriatic: numerous bays and sandy coves, moderate weather year round, and the crumbling reminders of just how widely Rome had stretched so many eons ago.
Not as touristy as islands like Brac to the south because of its lack of fresh water, Dugi otok makes a unique getaway from the mainland (a refreshing possibility when you're speaking about Croatian islands). Once you arrive, head east to either Sali or Bozava to find your best home-base options. The biggest reason to wind up here is Telascica nature park, although we're sure you could partake in staples like locally produced figs, cheese, and wine and be satisfied. Telascica is a collection of over two dozen wind-shielded bays, saltwater lakes, and craggy cliffs - the type of place you know will make up for any delays the airline may have put you through.
Although hiking is a possibility, the appeal here is the diving and snorkeling. From Telascica Bay to nearby Garmenjak island, you'll see an excellent selection of marine life, including sponge, crayfish, and (if you're lucky) the occasional octopus. There is a diving center in Sali for those who are intrigued.
Note:If you can pack it into a day, combine an excursion into Telascica with a visit to the Kornati Islands, especially if you're looking to do multiple scuba dives.