Here is a great app with trails in the Canary Islands. On Wikiloc.com people can share and upload GPS trails. The system works all over the world, and in addition to hiking trails, it offers cycling, running, off road… and many other trails.
When you’re looking for “Tenerife Bosque Encantado” for instance, you get a couple of options uploaded by different people, telling you the milage they made and the difficulty of the trail.
Depending on the cell phone from which the trail was uploaded, the divergence of the route is smaller or bigger. However, this usually does not bother a lot.
The apps are available for Android or Iphone and can be downloaded either in Spanish, English, Portuguese, Catalan, French, German or Italian.