Off the westernmost point of Tenerife, the snorkeling at Punta de Teno is considered by many locals to be the best on Tenerife. Many tourists totally miss the snorkeling opportunties here since they are so focused on the lighthouse nearby. If you happen to hit Punta de Teno on an exceptionally calm day, it could be possible to snorkel around the corner from the lighthouse to see bigger open water fish. Note, the rough access road out to Punta de Teno has periodically closed over the past few years due to storm damage.
Overall, the snorkeling around Tenerife is good year-round and the water temperature is pretty consistent. You may want a thin neoprene shirt during winter months. During certain times of year, there may be opportunties to snorkel with either pilot whales or with butterfly rays in the waters of Tenerife, so make sure to check with the dive shops for more info. Also, the waters of Tenerife are frequented by five types of turtles including loggerhead turtles, green sea turtles, leatherback turtles, hawksbill turtles and olive ridley turtles.
Since the Canary Islands are actually part of Spain, the best way to fly to the islands is through an airport in Spain. There are flights to all of the main Canary Islands directly from one Spanish airport or another. Of course, Madrid offers the best connections. Presently, there are not direct flights from the USA to the Canary Islands. Once in the Canary Islands, the best way to go between islands is still by inter-island flights. There are some boat services that do go between the islands as well. TIP: For your safety, most of the Tenerife snorkeling dive sites require snorkelers to have a diver-down flag marker. The waters around Tenerife are very popular with windsurfers and boaters, which has resulted in some snorkeler deaths over the past few years.
Overall, Punta de Teno is the 16th most popular snorkel dive spot of all 39 snorkeling dives in Canary Islands.