What is the difference between roaming and international calls?
Roaming applies to the cases of use outside Spain in the emission/reception of calls and SMS, as well as data browsing.
International calls you make from Spain (or from outside Spain in Roaming) to any mobile or landline that is not Spanish, the cost will be additional to your tariff unless you have contracted a bonus of international minutes.
You can check the international call rates in the search engine.