Personally I would not take a dog onto any beach in Spain.  We did so several years ago and whilst having a run around she must had disturbed a sandfly as a few weeks later a random check at the vets highlighted that she had leischmania.  Now has to have regular blood checks and will be on pills for the rest of her life.  The beach was the only place we could think of as to where she could have been bitten, and she was wearing one of those expensive Excalibur collars !!