Restaurants with good seafood that are not super expensive
What about Quincy Market where I ate the best fish and chips and clam chowder ever. This unique market is located to besides Faneuil Marketplace Quincy Market which adds value to the place. Try it! you wont regret it!!
If you just want straight up cheap oysters, don't fall into the tourist traps! You'll be paying over the top prices for the same stuff you can get for $1!
However, do NOT miss Legal Sea Foods. I have had chowder all over the city and legal for sure lives up to the hype. Also a decent touristy place that has (mostly) great food, Quincy Market food court.
Neptune Oyster is a go to but always has a line even if it doesn't look like it. Therefore I go to Rabia's Seafood/Oyster Bar & Italian Restaurant next stood for a good chilled raw platter. You can't go wrong with legal seafoods for standard fare. I like the location at the mystic river and legals harbor side.
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The Daily Catch is nice. There are two (Hanover St and Northern Ave). IMHO, Hanover is nicer. Order the Sicilian Swordfish.