This place is packed on Saturday mornings. If you don't get there in the morning, then you miss out on the best things. Farmers come in and sell the freshest things. You can get incredibly fresh seafood here, fresh meat, fresh vegetables, fruit, etc. You can even get the butchers to cut you whatever part of the cow you want and how you want it done. It is incredible. There are tons of stores that are only open on the weekends and they have unique items. There are many seafood vendors and St. Lawrence Market is has probably one of the best seafood selections that I've ever seen and I've been to the markets in Seattle and in Baltimore. Seattle is probably better but it is windy as hell there. Everything is fresh and just looks unbelievable. The bakeries have the freshest loaves of bread and they taste delicious.
Parking is nearly impossible so expect a nice wait in the parking lot for someone to leave if you're lucky.