I searched the forum but didn’t see anything on this possibly looking for 1/2 day boat trip sightseeing out of Kinsale this month for two couples. Are there ferries to islands? First time in Kinsale
From Kinsale, there is a harbour tour or you can charter a boat to go fishing, but that's about the extent of the options.
Other than the small, uninhabited Sandycove Island, there are no islands near Kinsale.