Drive down Overseas Highway past mile marker 58 in the second week of September and something is different at Grassy Flats. The dining room lights are off. The reservation line goes to voicemail. If you didn't know better, you'd think the resort had closed for good.

It hasn't. The Rhum House, the oceanfront restaurant at the heart of Grassy Flats Resort, shuts down every year for a stretch in the fall. This year it's September 8 through October 9, a closure that runs about five weeks. Upstairs, the Palm Deck rooftop bar has already been dark since early summer and won't reopen until November 1. For over a month, the fanciest kitchen on this stretch of Grassy Key simply stops cooking.

Here's what most visitors never notice, because most visitors aren't here in September: the island doesn't actually go quiet. Directly behind the Rhum House's darkened dining room, the Grassy Key Land and Sea Market keeps its lights on from 6 a.m. to 9 p.m., seven days a week, all year, storm season included. Same ownership. Same butcher. Same supply chain that stocks the fine-dining menu when it's running. The market is the reason a restaurant can afford to close for a month and the neighborhood still eats well.

That's the part worth understanding if you live here, because it explains a pattern locals keep bumping into every fall without quite naming it.

One Operator, Two Different Businesses

Grassy Flats, the Rhum House, the Palm Deck, Bongo's, Keys Cable Park and the Land and Sea Market all trace back to the same person: Matt Sexton, a former professional kiteboarder and wakeboarder who built his first restaurant to keep guests fed at his adventure park down the road. What he's assembled since is less a collection of separate businesses than one operation with two speeds.

The Rhum House runs on the resort calendar. It's built for oceanfront dinner service, reservations, a wine list sourced from small family vineyards, and a kitchen that needs a real break after the winter and spring rush. Its current hours, when it's open, are Thursday through Monday evenings, with Tuesdays and Wednesdays off even in season. That's already a lean schedule before you add the five-week fall closure on top of it.

The market runs on a different clock entirely. It's a butcher shop, fish house, bakery, deli and grocer under one roof, and it doesn't observe the resort's rhythm. Third-generation butcher Mike Shaner, who runs the meat counter, is the same person cutting the proteins that eventually land on the Rhum House's plates when the restaurant is open. When it's not, the counter keeps selling the identical cuts, and on Tuesdays and Wednesdays, when the dining room is dark even during the regular season, you can pick a piece of protein from the case and have the market cook it to order for the cost of the item plus a 20 percent preparation fee. Same butcher, same product, different room.

This is the mechanism. The high-end restaurant is allowed to be seasonal because the market absorbs the demand that doesn't disappear just because the tablecloths do.

The Building That Sat Empty for Seven Years

There's a second layer to this that only makes sense if you know the building's history. Before it was the Land and Sea Market, that storefront at 58152 Overseas Highway was the Grassy Key Outpost. Before that, it was the Dairy Bar. After Hurricane Irma hit in 2017, the building sat shuttered for seven years, a familiar sight to anyone who's driven past it more times than they can count without giving it a second thought.

Sexton had his eye on the space for years before he finally reopened it, soft-launching around the 2024 holidays and building toward a full menu through early 2025. The butcher counter and coffee program came online first. Pastries and hot meals followed once the kitchen was fully staffed, including a pastry chef, Hailey Pacyna, who moved her operation over from the Rhum House to bake there daily.

What that timeline tells you is that the market wasn't designed as a side project or a gift shop. It was built, deliberately, to be the piece of the operation that never has an off-season. A seven-year vacancy on a highway corridor with this much drive-by traffic isn't nothing. Reopening it as a 3,000 square foot market that runs longer hours than the flagship restaurant is a bet that locals need a version of this business that doesn't take a break.

What's Actually Open Right Now

If you're trying to plan meals for the next five weeks, here's the practical version of all this:

• The Rhum House is closed September 8 through October 9, 2026. No dinner service, no reservations, until it reopens.
• The Palm Deck has been closed since early summer and won't reopen until November 1, so the rooftop cocktail and sunset routine is on pause for a while longer.
• The Grassy Key Land and Sea Market is open daily from 6 a.m. to 9 p.m. throughout the closure, serving breakfast, lunch and dinner from the counter, plus the butcher case, fish house and Grassy Grinds coffee program.
• On any night, you can buy a protein from the case and have the market cook it, which is functionally the same kitchen output as the Rhum House without the reservation.

If you're coming from Coco Plum or points closer to Marathon proper, the market sits directly on Overseas Highway, easy to fold into an errand run rather than a special trip. Grassy Flats Resort itself sits just steps from Coco Plum Beach and a two-minute drive from Curry Hammock State Park, so a beach afternoon or a park walk pairs easily with a stop at the market on the way back.

Why This Pattern Matters More Than It Looks Like It Should

It's tempting to read a restaurant's fall closure as a simple seasonal footnote, the kind of thing every waterfront kitchen in the Keys does after a long tourist season. That's true as far as it goes. What it misses is that the closure only works because someone built a second business specifically to catch what falls through when the first one steps back.

That's a different kind of local knowledge than knowing which restaurant has good stone crab. It's understanding that the food identity of this particular stretch of Grassy Key isn't tied to one dining room. It's built into a small cluster of businesses under one roof, engineered so the island keeps functioning even when its most photographed kitchen is dark.

For anyone who's lived here through a few of these fall closures, that's probably not a surprise anymore. It's just how the place works. But it's worth saying out loud once, because it's the difference between assuming the island slows down in September and knowing exactly where to go when it does.

The Rhum House will reopen October 10. The Palm Deck follows on November 1. Until then, the market keeps its lights on, the butcher keeps cutting the same fish, and Grassy Key keeps eating like nothing changed.

If you're weighing a move to this stretch of the Middle Keys, or you already call it home and are curious what your property could be worth in a market this specific to local rhythms, Jessica Borraccino knows Grassy Key at this level of detail because she works here every day. Let's connect and schedule your free consultation.