Post Restante

[Horse/2]

Does anyone know the address of the main post office in Puerto del Carmen Lanzarote

[heathfield]

If you're sending stuff, the precise address doesn't matter. See here

If you're picking stuff up, ask a local, and follow the advice on names in the link.

[Buenchico]

It's shown by the 'envelope' on this map:
http://www.puertodelcarmen.com/img/di-mapa-B.j pg

That makes the address:
Oficina de Correos,
Avda Juan Carlos I,
Puerto del Carmen,
Lanzarote,
Islas Canarias

There should probably be a postal zone as well but, as Heathfield indicates, the postal services of any country usually know where to find a post office ;-)

Chris