Yes, in the last two high seasons, the Grand/Gourmet Marches have been open on Sundays until 6 pm. In the low season, it seems to revert back to a 2 pm closing.
By the way, the Gourmet Marche in Porto Cupecoy is in the process of converting to a Carrefour.
My wife and I live in St. Maarten during the winter and in the Boston area the rest of the year.
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