In the middle of the month of August, always coinciding with the 15th, the day of the patron saint Nuestra Señora de la Fuensanta, the patron saint's festivities are held. These festivities originated in the mid-18th century, thanks to Carlos III, who granted Coín the privilege of celebrating them in 1765.

On these dates Coín becomes a place for meeting and fun, both for the locals and for visitors. An extensive programme of activities, competitions, sports and leisure events occupy these summer days.

For some years now, on the morning of 15 August, the peculiar competition-tasting and auction has been held to determine the best Huevo de Toro tomato of the season.

The fair concludes on the 15th with the celebration of a mass in the Plaza Bermúdez de la Rubia, in honour of the patron saint, which will continue with a night procession in honour of her day and these festivities.