UKC

Have booked Ferry to Northern Spain in August - hoping to go to Picos or Pyrennes or possibly a combination of both (have 2 weeks). For hiking, single pitch sports routes, cycling. I'm reading alot about how crowded the Picos is in August. Any recommendations for a nice base in either that would be away from the crowds? Haven't been to either area before. 

I can't be much help unfortunately, except to say that in August both will be heaving busy, as that's when all of Spain stops working and heads to the coast and/or mountains. Finding a "nice base away from the crowds" will be very difficult. The Pyrenees represents a bigger area so you'd have more chance there, assuming you avoid the fleshpits of Benasque, Monte Perdido or Gavarnie (on the French side). 

I was in the picos in August 2 years ago and the didn't think it was too busy. Talking to some Spanish people there I got the impression it was considered a bit of a backwater in Spain. We had to que for about 20-30 mins for the cable car at Fuente De but that was as bad as it got. The crags were all very quite, apart from Naranjo del Bunes, but even then we had the route to ourselves until overtaken by a guided party half way.

You can find quieter areas in both Picos and Pyrenees, though August is as busy as it gets for both. 

If Picos, stay away from the central massif. The western massif is gorgeous and much quieter.

As others said above, in Pyrenees stay away from honeypot areas such as Ordesa, Monte perdido, Aneto, Aigues Tortes etc. You could try the bit where the Vasque Pyrenees turn into the Aragon Pyrenees.

My info is all about 20 years old, so take everything with massive amounts of salt!

I've never been to the Picos but have spent quite a bit of time in the Pyrenees both in France & Spain. As others have said, some places will be very busy in August (eg Gavarnie, Ordesa) but usually a short walk will find somewhere quiet - even near Gavarnie we've sometimes been the only rope on a crag (midweek).