Porto is better for second-hand shopping when you treat it as a hunt, not a checklist. The markets are on different days and in different parts of town, and older guides still send people to places Feira da Vandoma no longer uses. Check the date before you set out.
Two fairs, two different mornings
Feira da Vandoma is the Saturday flea market, now at Praça Vandoma beside Nasoni metro in Campanhã, 08:00–13:00. It is a broad jumble of second-hand goods, not a curated antique shop. I would go early, wear shoes you do not mind getting dusty, and leave room in the bag. Map to Praça Vandoma.
For older objects rather than a general flea-market mix, the municipal Mercado de Antiguidades e Velharias is on the third Saturday of each month at Praça do Dr. Francisco Sá Carneiro, 08:00–18:00. That is a different market on a different side of the city. Check the municipal page in case of a changed date. Map to the antiques market.
Shops between market days
PortoVelho, at Rua dos Mártires da Liberdade 83, is a useful browse for old books, records, postcards, porcelain, collectibles and small curiosities. Its site lists the current opening hours; it closes at weekends, so do not save it for Sunday.
For a more serious antiques showroom, Antique Porto is at Rua Nossa Senhora de Fátima 381, but visits are by appointment. This is not a casual walk-in stop; contact the shop first through its official page.
What I check before buying
For clothes, turn the item inside out: seams, lining, zips, cuffs, stains and that damp-storage smell matter more than the label. For furniture, check drawers, joints, water damage and whether it will fit through your Porto apartment’s door and stairwell. A beautiful wardrobe that cannot get past the landing is still a bad purchase.
With old azulejos or architectural pieces, ask where they came from and ask for documentation. If the seller cannot give a clear answer, leave them. Porto has enough buildings missing their original tiles already. For electronics, test before paying; for records and books, inspect condition rather than trusting the cover.
My best practical advice is to decide what you can carry before you start. Small ceramics, prints and postcards travel well; furniture does not. And if you only like an object because the stallholder has wrapped it in a good story, take one lap around the market before deciding.
