There is a Mercadona supermarket less than 5 mins from the airport. As you leave the airport and come to the roundabout take the exit for San Javier. Straight on at the next roundabout then at the next roundabout turn left into shopping centre and Mercadona is in there.
Also restaurants etc in shopping area and just outside. Can recommend the Chinese buffet inside the shopping area. Best in the area ( in my opinion) and bottle of wine per couple when you leave!!! Excellent when you have just arrived or going back to airport.
To get back to motorway just reverse instructions or turn left from shopping centre into San Javier and follow signs. If you are not sure of the way it is probably easier to head back towards airport.
Jean
Jean