La Cañada used to have Intersport (not Decathlon) but it closed about 6 months ago. It was replaced by Sport Zone, but their snorkeling assortment is limited.
Aug 31, 2011 Rating
Decathlon for excellent sports equipment by: LindsayinSpain
Hi, I get all our snorkelling and sports gear in Decathlon, I think your nearest store is in La Cañada.
Have fun!
Aug 31, 2011 Rating
Diving equipment Marbella by: Franck
There is a diving center in Marbella´s Puerto Deportivo called buceaenmarbella. You can take classes there or rent equipment from them.
Another good store is Decathlon in Fuengirola or near Malaga airport, but it is further out.
Aug 31, 2011 Rating
snorkeling in Marbella by: Marbella Family
We are not divers, so I am unfamiliar with the scuba diving and snorkeling shops in Marbella. I would first check El Corte Ingles in Puerto Banus, because this is the place to go to find just about anything.
I have seen a number of sport shops around Marbella and San Pedro and will see if I can get a recommendation. You can also try Decathalon in Fuengirola. This is a large sport store that provides loads of equipment and surely includes a diving department.