SeaGlass Cove
Homes for Sale in Marathon, FL
True comps, carrying-cost math, and listings before the portals.
SeaGlass Cove is a rarity for the Florida Keys: an entirely new, gated ownership community. Under the county's ROGO growth-management system, permits to build new dwellings in Monroe County are strictly rationed, so a purpose-built enclave of 14 brand-new oceanfront residences is close to the ceiling of what the market produces. When we last checked, the developer reported construction complete, open houses underway, and pricing starting from about $3 million.
For a buyer, the read is simple. This is not a large master-planned community with a long absorption runway; it is a fixed set of 14 homes on Grassy Key. Scarcity is the whole story, so the questions that matter are lot/position within the enclave, the ownership and HOA structure, and whether the weekly-rental permission fits your plan. There is no long resale history to price against yet, which is exactly why we track it here.
Who SeaGlass Cove is best for.
Best for
- Buyers seeking a new-construction, gated oceanfront home in the Marathon / Grassy Key area at the $3 million-and-up level
- Second-home buyers who want the option of permitted weekly rentals to offset carrying cost
- Shoppers who value the scarcity of a finite 14-home enclave over a wide menu of choices
Probably not for
- Buyers looking for entry-level or mid-priced Keys inventory
- Anyone who needs an established community with a long recorded resale history to price against
- Buyers who require confirmed HOA figures, ownership structure, and rental rules before they will engage — those were not published at discovery
Life at SeaGlass Cove
- Gated private entry · Gated oceanfront enclave of 14 residences on Grassy Key.
- Private sandy beach · Private white-sand beach fronting the Atlantic Ocean, shared by the enclave.
- Resort-style pool · Resort-style community swimming pool.
- Pickleball court · On-site pickleball court.
- Open-water Atlantic views · Three-story residences positioned for direct open-water ocean views.
- Two-car garages · Each residence includes a two-car garage; roughly 4,800+ sq ft, 4-5 bedrooms.
- Weekly rentals permitted · Developer states weekly rentals are permitted; confirm against association documents and current Monroe County / City of Marathon vacation-rental rules.
Based on public records and builder announcements.
The SeaGlass Cove buying strategy.
If we were buying in SeaGlass Cove today, this is the order of operations we would run for our clients.
Underwrite the condition first. Price the roof, HVAC, and systems honestly before judging any list price; condition swings value here more than square footage alone.
Match the home to real comps. Recent sales of similar condition and lot, not the asking price, tell you what a home is worth.
Move deliberately, not desperately. Neither side has a decisive edge, so a well-prepared, fairly-priced offer wins without overpaying.
Line up financing and inspection early. A pre-approval and an inspection plan let you act fast and negotiate from evidence.
Keep an agent in your corner. The listing agent works for the seller; we represent you and prepare a hand-built valuation before any offer in SeaGlass Cove.
Fourteen Homes, One Enclave
The detail that makes SeaGlass Cove worth a page is its scarcity and structure. Monroe County's ROGO permit system rations new residential construction across the Keys, which is why brand-new, purpose-built ownership communities almost never appear here. SeaGlass Cove is a fixed enclave of 14 residences behind a gated entry on Grassy Key, an oceanside island inside Marathon. That fixed count matters: there is no phase two, so buyers are choosing among a small, finite set of homes rather than a rolling release.
The product itself is large for the Keys. Floor plans run four and five bedrooms across roughly 4,800+ square feet on three levels, each with a two-car garage, positioned for direct open-water Atlantic views above a private beach. Shared amenities marketed by the developer include a resort-style pool, a pickleball court, and beach access. The developer also states that weekly rentals are permitted, which is unusual in the Keys and can matter to buyers weighing personal use against rental income.
Two things should be confirmed in writing before any deposit. First, the ownership and carrying structure: whether the residences are sold fee-simple or as a condominium, and the amount and scope of the HOA or association assessment, were not published at discovery. Second, verify the rental permission in the association documents and against current Monroe County and City of Marathon vacation-rental rules, since transient-rental eligibility in the Keys is governed by specific licensing and can change. Developer disclosures note that plans, amenities, and pricing are subject to change.
The location and the amenities are priced into every listing in SeaGlass Cove. The deal is won or lost on condition, the comps, and the renovation math.
Why work with Momentum here
For a finite, high-value enclave like this, the value of a local agent is diligence and positioning. We can pull the recorded documents to confirm whether SeaGlass Cove is fee-simple or condominium, get the association budget and assessment in writing, and read exactly how the weekly-rental permission is worded before you rely on any income assumption.
We also help you compare the remaining SeaGlass Cove homes against resale oceanfront options elsewhere in Marathon, Grassy Key, and Duck Key, so a roughly $3 million-and-up decision is underwritten on verified numbers, flood and insurance realities, and the real carrying cost, not on a brochure.
SeaGlass Cove in 15 seconds.
HOA, CDD & Fees
- Mandatory HOA — confirm current dues
- Any club/amenity membership is billed separately
Confirm the current HOA dues, exactly what they cover, and any CDD bond or special assessment for a specific address before you offer.
Tools for a SeaGlass Cove buy.
Free calculators to pressure-test the real cost before you tour.
Selling here is won on condition and pricing to real comps, not an automated estimate. The right number comes from closed SeaGlass Cove sales matched to your home.
Price it to the comps and condition, not an automated estimate.
If you are thinking about selling in SeaGlass Cove, the right list price comes from recent comparable sales matched to your home's condition and location, not an automated estimate.
What is your SeaGlass Cove home worth?
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Should you buy in SeaGlass Cove?
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More Marathon & The Florida Keys & Monroe County guides
Compare before you commit - every guide covers pricing, HOA/CDD, insurance posture, and fit. Browse all of The Florida Keys & Monroe County or the full Neighborhood Finder.
The real cost & risk here
Before the list price, the Florida math the portals skip. These are Monroe County typicals — your exact home, flood zone, and insurance quote will vary, so verify each before you offer.
Check it for your address: look up your flood zone (FEMA) · insurance by county · true-cost calculator · Monroe County scorecard.
County typicals from Momentum’s Florida housing data (Zillow & Realtor.com aggregates, Census, FRED), updated monthly; insurance modeled. Flood zone is property-specific — always confirm via FEMA.