Saint John's Eve on Xeraco Beach (Nit de Sant Joan)
Spain's magical midsummer night on the sand: as midnight nears, crowds gather on Xeraco beach for the Saint John bonfire tradition, with two large municipal bonfires lit (one at the north end, one to the south). Note that private bonfires are banned, so come to enjoy the official fires, the sea and the party atmosphere.
The night of 23 June is when Spaniards mark the summer solstice, and on the Valencian coast that means heading down to the sand after dark. Thousands of people from Xeraco and the towns around it come down to the beach, where they light hundreds of small bonfires along the shore and see in the shortest night of the year. It's one of the busiest nights on the local calendar, and the whole stretch of sand turns into one long, smoky, good-natured party.
Bring a jumper for when the sea breeze picks up. The Town Hall and the festeros put on a mobile disco to keep things going into the early hours, so plenty of people stay on until first light comes up over the water. It's free, and easy to wander into.
Source: https://www.xeraco.eu/es/areas-y-servicios/cultura/fiestas/