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MASHTA ISLAND · · MLS B26058354
Listed by Coldwell Banker
BRING ALL OFFERS! Exceptional waterfront opportunity in prestigious Key Biscayne. Set on a 15,000 sq. ft. lot with 100 feet of water frontage, this residence offers open-water views, direct Biscayne Bay access, and no fixed bridges to the ocean. Currently undergoing a complete renovation, it will feature modern finishes, impact windows and doors, new systems, spacious living areas, a chef's kitchen, and luxurious bathrooms.
Enjoy a private dock, deep-water access, pool, breathtaking sunsets, and an unmatched boating lifestyle in one of South Florida's most desirable communities One of the most compelling waterfront opportunities currently available in all of Key Biscayne. Perfectly positioned on the exclusive and highly coveted Mashta Island, this exceptional property offers approximately 100 feet of prime waterfront, deep-water dockage, direct Biscayne Bay access, and no fixed bridges to the Atlantic Ocean, creating an unparalleled opportunity for boating enthusiasts and yacht owners. Mashta Island has long been recognized as one of South Florida's most prestigious residential enclaves, offering exceptional privacy, quiet tree-lined streets, oversized waterfront estates, and immediate access to the open waters of Biscayne Bay while remaining only minutes from Brickell, Downtown Miami, Coconut Grove, Coral Gables, Miami Beach, and Miami International Airport. Very few neighborhoods offer this combination of island living, security, boating lifestyle, and proximity to the city's financial and cultural centers. The residence is currently on renovation designed to transform the property into a contemporary waterfront estate while preserving the exceptional value of its location and oversized waterfront parcel. This is substantially more than a cosmetic renovation. The project includes major improvements throughout the residence, including redesigned living spaces, upgraded electrical and plumbing systems, new HVAC equipment, impact-resistant windows and doors, premium flooring, modern architectural lighting, designer finishes, and a completely reimagined interior intended to meet today's luxury lifestyle expectations. Upon completion, the home is anticipated to offer spacious entertaining areas, beautifully appointed bedroom suites, bathrooms, an impressive chef's kitchen featuring custom cabinetry, premium appliances, elegant countertops, and thoughtfully designed indoor-outdoor living spaces that maximize the spectacular waterfront setting. The property's exceptional orientation provides beautiful water views and unforgettable sunsets while creating an ideal environment for entertaining, family gatherings, and year-round outdoor living. The expansive backyard offers generous space surrounding the swimming pool together with multiple areas for outdoor dining, lounging, and enjoying the waterfront lifestyle that has made Key Biscayne one of the most desirable residential communities in South Florida. For boating enthusiasts, few properties can offer the combination of oversized waterfront, private dockage, deep-water access, and unrestricted navigation to Biscayne Bay and the Atlantic Ocean without fixed bridges. Whether accommodating a large sport yacht, cruising yacht, center console, or multiple vessels, the waterfront configuration provides flexibility rarely available in today's market. Key Biscayne continues to be recognized as one of South Florida's most exclusive island communities, celebrated for its pristine beaches, excellent schools, private clubs, marinas, tennis facilities, parks, bicycle paths, restaurants, and relaxed coastal lifestyle. Residents enjoy the unique advantage of living within a peaceful island environment while remaining only a short drive from Miami's world-class shopping, fine dining, cultural institutions, private airports, international business centers, and professional sports venues. The supply of premium waterfront homes on Mashta Island remains extremely limited due to the neighborhood's established character and finite number of waterfront parcels. As a result, opportunities to acquire large waterfront lots with substantial dockage and direct ocean access continue to be highly sought after by both domestic and international buyers. The combination of location, waterfront dimensions, boating accessibility, oversized lot, and comprehensive renovation creates a property with exceptional long-term appeal. Showings are strictly by appointment with the Listing Agent.. All measurements, dimensions, lot size, square footage, waterfront frontage, dock dimensions, room sizes, zoning, taxes, permits, specifications, plans, renderings, and property information are believed to be accurate but are not guaranteed and should be independently verified by Buyer. Renderings, conceptual plans, floor plans, specifications, and construction updates are available upon request when applicable. This offering represents an extraordinary opportunity to secure one of Key Biscayne's waterfront residences . Whether as a primary residence, seasonal retreat, or long-term investment, this property combines one of South Florida's most desirable locations with an outstanding boating lifestyle and exceptional future value. Bring All Offers.
The propertyAs the MLS records it
$110,235 per month
30-year fixed, 7.24% interest
The calculator opens on the national average rate for a 30-year fixed-rate loan: 7.24% for the week of October 29, 2026. Source: Freddie Mac, Primary Mortgage Market Survey ↗
For illustration only: an estimate, not a loan offer or a quote. The tax is the last annual bill the MLS records for this property; in Florida a property is reassessed when it is sold, so a buyer's tax will differ. Insurance is not estimated: it is included only when you enter your own quote. The rate is a national weekly average, not the rate a lender will offer you: change it to the one you are quoted.
REQUEST A TOUR
Showings of 631 N Mashta Drive, Key Biscayne, FL 33149 are by appointment. Send the request here, call or write on WhatsApp: Julian Acosta, real estate advisor with Compass, answers within one business day to confirm a day and a time.
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| Year | Median price per SF | Closed sales |
|---|---|---|
| 2020 | $803 | 54 |
| 2021 | $964 | 109 |
| 2022 | $1,220 | 60 |
| 2023 | $1,249 | 30 |
| 2024 | $1,321 |
Homes of the same kind on the market nearby, the nearest in price first.
AS OF OCT 30, 2026 · MLS
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1 / 3ACTIVENewThe information on this page is supplied by the Southeast Florida Multiple Listing Service of the MIAMI Association of REALTORS®. It is deemed reliable but is not guaranteed accurate by the MLS, and it may have changed since the date above. It is provided for your personal, non-commercial use and may not be used for any purpose other than to identify properties you may be interested in purchasing. This listing is held by Coldwell Banker. Julian Acosta is a real estate advisor with Compass.
A listing shown here may be held by a brokerage other than Compass. To report an error in this listing's information, write to julian.acosta@compass.com.

















































49 PHOTOGRAPHS
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| 2025 | $1,404 | 38 |
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| 2026 to date | $1,498 | 37 |
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These figures are the market's closed sales as the MLS records them: this building's for a unit, a gated community's for a home inside one, and otherwise the sales of this kind of property in the home's market — for a home at $2,000,000 or more, only that market's sales from that price up. Which of these it is, is said above the figures. No snapshot is drawn from fewer than 5 sales of the last twelve months, and a median price per SF is stated only from 3 sales that state a living area. They are not sales by Julian Acosta, they are not an appraisal, and they say nothing of this home's price.
These are the public schools whose attendance zone holds this listing's location, as Miami-Dade County publishes the zones. A zone is not a guarantee of enrollment, the district can change it, and a listing's point on the map can sit a few meters from its lot: confirm the school with Miami-Dade County Public Schools before you rely on it. Distances are straight lines. The page states no rating of any school.
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