There's lots of boat trips available - a catamaran too!
There's loads of little agencies where you can find out about the trips and book them.
Many hotel/apartment receptions have that facility too, so you maybe able to book from where you are staying.
We went on a boat trip years ago - all day, all drink and food included.
We sailed all round the coast, and dropped anchor in a little cove where the crew did a BBQ whilst people swam and/or
played beach games that the crew also provided.
The drinks were fine
the food not so fine for some (sardines and/or chicken - delicious - with salad)
We had a fabulous day, but for the life of me I couldn't tell you how much it was.
It wasn't cheap, I remember that, but it really was a great day.
If you do go on a boat trip, don't forget your suncream, hat and cool clothes should you need to cover up because you
are in the sun ever such a long time.
Hopefully someone will come along who has been on a trip recently and can give you an idea of the prices.
Enjoy your holiday!