Some of us from the walking group took the guided tour through Timanfaya yesterday. You go from the visitor centre on a gentle stroll through the park in groups of 6 or 8, led by one of the incredibly knowledgeable guides, who have been doing the 3 times a week walk for 20 years! The walks are free. You need to take a passport or ID card to sign the disclaimer form) a hat, water and closed toe shoes.
Our guide was Nino, who was superb. Here's a video of him in action - he kept this up for over two hours!
http://www.youtube.com/watch?v=P2CGWon4W24Here's the link to book a walk. I can really recommend it.
https://www.reservasparquesnacionales.es/real/ParquesNac/usu/html/listado-actividades-oapn.aspx?ii=6ENG&cen=6
