Sant Boi de Llobregat Main Festival Activity · Sant Boi de Llobregat, Baix Llobregat, Barcelona Image of Sant Boi de Llobregat, not of the place itself. The Festa Major (main festival) of Sant Boi de Llobregat is held on 20 May, with popular and traditional events that bring together the whole municipality. A week later comes the Festa de la Capvuitada, which extends the celebrations, along with the additional festival in honour of Sant Baldiri, linked to the local heritage of this Baix Llobregat municipality. 15-17 de maig i 20 de maig Photo: Enric (CC BY-SA 4.0) What to see and do in Sant Boi de Llobregat