We were on SXM on Christmas Day last year, and I'm pretty sure all the regular grocery stores were closed on Christmas Day. We were at Grand Marche fairly late on Christmas Eve, and it was PACKED. I think they were supposed to close at 6 PM on Christmas Eve, but I recall hearing afterward that they were actually open later than that last year, as the store was full of people. I don't recall Boxing Day, but I think they were open on Boxing Day. Suggest you contact Jeannie at Shop N Drop and have her deliver first night supplies, or bring them with you.