The OTT service will make classic HBO series including The Sopranos (pictured), The Wire and Entourage available immediately. The deal covers 500 hours of HBO fare in total.
Wuaki said the HBO agreement was a first of its kind in the Spanish market.
In May, it announced a similar deal with HBO for its UK service.
Wuaki is available in Spain, France and the UK. It is owned by Japanese e-commerce giant Rakuten.