Near Costa Adeje on the southwest coast of Tenerife, the snorkeling at El Puertito de Armeñime offers a sheltered cove that is sea turtle habitat. Also, known as Turtle Bay, the best snorkeling on Tenerife is located just off Playa Puertito. The bay is home to a half-dozen juvenile green sea turtles seeking shelter. Overall, 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. While it can be accessed from the beach, there are also many snorkel tour boats about in the center of the small bay. The water clarity does vary greatly depending upon waves, wind and rain - if you hit it with low surf and low wind after days without rain, then the water clarity is absolutely exceptional.
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.
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, El Puertito de Armenime is the 10th most popular snorkel dive spot of all 39 snorkeling dives in Canary Islands.