Glass Bottom Boat Cruise
There’s a glass bottom boat offering daily cruises from the Ayia Napa Harbour. I didn’t go myself, but the price is €10 per person I think.

The daily trips head out from the harbour in the morning – 10/11ish and you are taken to Cape Greco and Famagusta to see both places from the sea.
Just be sure that the sea is calm before you book your trip, if not it can become nauseous. I’ve heard stories about people puking…