Resorts tend to be quite quiet, not full of clubs. If the teen likes low key where an evening out is mostly dinner and a few drinks, with the odd Greek night and entertainer, the occasional noisy bar, great. During the days, sunbathing, swimming, water sports, boat trips, sight seeing.
We stay in Scala, good for a relaxing holiday. Boat trips to island of Ithaka from the beach, including swim stops. Yes you need neoprene beach shoes.
You can go on trips to see where Captain Corelli's Mandolin was filmed, also up into the mountains to see the golden eagles and the wild horses (descendants of the ones abandoned after the occupation during the WW2.) Scenery is breathtaking.
We have already booked to go this September. Last time we went two years ago it was 38 degrees! That was a bit unusual though. It will be extremely hot in July and August.