In a word, No! The average age of the tourist used to be very relatively high but slowly the last years has dropped significantly meaning there are more businesses opening slowly offering fun and activities for younger people. Still, Kefalonia is mainly a family and quiet destination.
There are a few nightclubs on the island usually situated in the capital of Argostoli around Lassi and Skala area and a lot of beach bars on the most popular beaches. Most of the towns and villages have cafes and bars that stay open late with low key atmosphere. It is as easy to find non-alcoholic drinks as it is to find alcoholic ones.
Greek nightlife tends to centre on eating out, having a coffee or a beer, ouzo or tsipouro and meze with friends. Very often though families join the local music and dance festivals that take place around the island all year round but mainly in the summer season (Robola wine, moustalevria, gastronomic, music and many art festivals).  Don’t miss the chance to participate in one of them and mingle and dance with the locals (check our events page to find one during your stay).