Sea Market (Mercat de Mar)
A seaside-themed open-air market spread along the town's central streets during the Festa Major, with stalls, crafts and a maritime atmosphere. Easy to browse for anyone, no Spanish needed.
Vilassar de Mar is an old fishing town, and for two days during the Festa Major its central streets fill with stalls that lean into that seafaring past. You wander Carrer Sant Joan and Carrer Anselm Clavé, poking through crafts, local produce and bits and pieces with a maritime slant. It's relaxed browsing, no schedule to keep to, and you don't need a word of Catalan to enjoy it.
The one thing worth turning up for is the sung fish auction on the Saturday morning, around eleven. A vendor calls out the catch in the old chanted style traders once used, and you can buy fresh fish straight off the slab. It's a small, genuine slice of how the town used to work, and a good excuse to be there early before the afternoon crowds drift in.
Source: https://www.festamajorvilassardemar.cat/programa-sencer-25