My wife and I just returned from a wonderful snorkeling holiday in Zakynthos. However, we would like to provide a few tips for future travelers. These tips should be taken with the caveats that we were visiting Zakynthos in June and there was very unusual weather in that it was a bit cloudy and rainy. In addition, my wife and I are quite enthusiastic snorkelers and can happily spend many hours in the water. With that information in mind, the Keri area is not the best for snorkeling because it seems to experience a bit of a rain shadow effect. That means that the west side of the island was often cold and cloudy, whereas the east side was sunny and warm. In addition, the winds were blowing in from the west, making the ocean very rough, while the east side was calm. The snorkeling around the Blue Caves is some of the best that we have ever experienced and we highly recommend it. The only drawback is that you have to constantly watch out for the tour boats. The area north of Agios Nikolas is absolutely beautiful and not at all crowded. We found that the coastline around Vassilikos was beautiful, but the snorkeling was disappointing. The snorkeling at Keri is OK, but nothing spectacular. If you do snorkel there, a tip is to snorkel around the island of Marathonisi. It took us ~1.5 hours and was a really nice swim. Overall, we had a fantastic visit and highly recommend the island.