Tenerife is sub-tropical, so has relatively stable temperatures and weather all year-round. The sea is clear and water temperatures normally stay in the 18-25 degree range.
The North-West of the island has at its centre the volcano Teno Alto which gives its name to the Teno National Park which surrounds it. There are a wide range of walks throughout the area, maps are available from tourist information points and they tend to be very well marked.
Garachico and up
The town of Garachico was a key port in the 17th Century for ships sailing on the outbound trip to the Americas. The port was destroyed when a volcano erupted in 1706 and lava came through the town in 7 places and went into the sea. There is a 2.9km walk up across the path of one of these lava streams to San Juan de Reparo. This might not sound like much, but it is steep in parts so is hard work. The climate change can be large as the 500m or so of height on the day we walked it meant changing from a nice day into a soaking wet one as we walked up into and through a cloud. On arriving at the top you can take a right and go a lookout point (mirador), which is probably great if you are not in a cloud...
Barranco de Masca
Masca is a small village up in the mountains which only got connected by road to the outside world 50 years ago. From there you can descend a gorge down to a beach which is only accessible by boat or on foot. This is a three-four hour tough walk, depending on how fit you are. You need to be wearing boots and be prepared to go down over some rocks. Take as much water as you can carry (there is nowhere to buy any once you leave the top), sun-cream, a hat and some snacks. The walk is spectacular, you descend into the ravine and then follow what seem to be endless turns and switchbacks until you finally hit the flat and come out to the sea. There are lizards, birds, flowers and a ton of other wildlife.
Options to get home from the beach include walking back up, boat ferries along the coast or kayak...
Kayaking by giants
We left the beach at the bottom of the Masca Gorge on ocean kayaks. The cliffs are called Los Gigantes (The Giants) and they live up to their name. We stopped halfway for a snorkel in a small cove at the bottom of the Barranco Seco where you can see a variety of fish. The route passes the nest of the one of the last 4 breeding pairs of a native Osprey species, some ocean fish-farms and some interesting geological formations (if any of those rocks your boat). With tired arms you paddle into port after a memorable trip.
Who to call?
Iván and Nayra run Teno Activo which specialises in adventure tourism in the Teno area. They run kayaking, hiking, diving and other activities. Personalised and very personal service mean they provide a top quality service and can make tailored packages to meet individual requirements. http://www.tenoactivo.com/ - +34 922 128 060
Where to stay?
The Vincci Selección Buenavista Golf & Spa (site here) is a new five star hotel situated in a select location on its own in the country side. Expensive, but the rooms, facilities and services are very good. The food is not five star in any way, and you would do well to take a 10min walk down to the coast to El Burgado to watch the sun set under a fishing net roof while eating fish taken out of the sea that afternoon.