Things you must have with you when driving in Spain
All foreign vehicles must have or carry the following items:
International Vehicle insurance, normally in the form of a Green card
(A Green card is recommended but not compulsory for vehicles from other EU countries. Within the EU, any vehicle insurance policy automatically includes third party cover throughout the European Union).
European union driving licence (or Swiss, Norwegian or Croatian), or an international driving licence.
Two hazard warning triangles to be used in the event of immobilization of the vehicle at the roadside.
A high-visibility waistcoat for driver and each passenger, to be put on in the event of breakdown or immobilization.
Front and rear seatbelts, that must be used.
For right-hand drive cars (from Britain or Ireland), headlamp converter for night driving
If you need glasses for driving, you must carry a spare pair in the glove compartment.
And note that.....
Use of mobile phones while driving is strictly forbidden (except fully hands-free units)
Children up to 12 years old must travel in the back of the car.