Would we be able to buy alcohol underage in Spain?

HI, myself (16) and my friend (17) are going to the Costa Del Sol this summer. We both occasionally drink at home as we get served sometimes without having to present any form of ID. I was wondering would we be able to get served in bars/restaurants or supermarkets while we are in Spain without ID. We are not interseted in getting drunk, just having the occasional drink while on holiday. Thank you. :)