You can rent a boat in Skiathos and go to all the great restaurants on the beaches.
You don’t need a license to rent a boat, and you’ll be given all the instructions you need.

It’s a unique experience you have to try for yourself.
What else could you do apart from hire a boat  by your self  is to  book a boat trip with a skipper who will show you the most beautiful parts of Skiathos and then suggest one of the best beachside restaurants where you can enjoy delicious food?