Quick, Simple and Cheap by nhcram
The metro goes all the way from the airport to the rest of the city so it is easy and fairly quick. We never had to wait long and the journey was a fraction of the price of either the bus or taxi.
A One-way ticket is ?1.15 and is valid for any one way journey within the whole network
(A bargain)
A map of the metro can be downloaded from the website.
The journey from the airport to the Puerto del Sol took about 40 minutes.