We took Poppy to south of France when she was six months. We had a great time (though it was a shock to have no lie in's or nights out!)
We hired a villa which i think makes more sense than a hotel. It meant i could cook for her (she'd just started weaning) and had a seperate room for her to sleep so we got a bit more rest (when ever we share a room now, at friends or hotels, we all keep each other awake!)
We got a heated pool (but Spain in May will prob be warm enough) and Poppy LOVED the water!!! So we just played in pool when not too hot, then kept her in shade during the sunniest times. We also used her travel cot outside in the shade, put toys in it, and let her play while we grabbed a few minutes of sneaky sun!!
We also bought a cheap fold up buggy to take too (got for a tenner!) rather than take my nice usual one. And we hired a car seat too.