I have just returned from a wonderful week in Split. But I don't think that October will be a good month for parties here ... too quiet.

Many watersports seem to be run by independent operators, and again, you'll be 'out-of-season' so there many not be as much going on as you might have hoped.

Sorry to be pessimistic, but I don't think that Croatia in October will suit you for beaches - almost ALL Croatian beaches are rocks so you won't get the sandy beaches you might have hoped for - nor for party nightlife in the evenings. I think you'll need to go a bit further south to Greece or west to the Balearics.

Wherever you go, I hope you have a great time.