Kassiopi is not in the same league as Kavos or even Sidari, so if it's nightlife you're after your best bet is to head for the harbour where bars like Deja Vu stay open later than most.
Angelo's Bar Great place where cocktails are popular. So are the regular pop quiz nights, or you can watch sport on satellite TV. Out of the Blue Cafe Just down from the square is this enjoyable wine bar and cafe, where you can also amuse yourself by checking your emails or surfing the internet. They also serve snacks.
TOP TIP: If you find Kassiopi too quiet at night, remember that taxis are cheap. Club together and take one to Sidari or Ipsos, and arrange to be picked up again later.