From Izola on the Slovenian coast two kinds of weekly trips can be made:
Follow first the Slovenian and then the Italian coast and make stops in: Trieste, Laguna di Grado, Laguna di Marano and Venice. On the way back it´s possible to cross the Mediterranean Sea and return to Slovenia, shortening the distance. Venice can’t be entered by boat, but the boat can be parked at the nearby harbour.
The total trip will take 6 days with a length of 300 km.
Follow first the Slovenian and then the Croatian coast and make stops in: Umag, Porec, Rovinj and Pula. To Pula is a distance of 110 km. After Pula it is possible to visit the island Otok Cres. The total trip is 220 km + 100 km for visiting the island.
In both directions enough harbours are on the way to spend the night. Average prices are around €40-50 per night.
For more information about Slovenia go here and here.
Umag, Porec and Rovinj: