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$18,500,000
10 Days On Site

631 N Mashta Drive
Key Biscayne, FL 33149

For Sale|Single Family Residence|Active
4
Beds
5
Total Baths
4
Full Baths
1
Partial Bath
2,255
SqFt
$8,204
/SqFt
1958
Built
Subdivision:
MASHTA ISLAND
County:
Miami-Dade
Call Now: 561-255-3438
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561-255-3438
631 N Mashta Drive631 N Mashta Drive631 N Mashta Drive631 N Mashta Drive
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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.

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Listing Snapshot
Price 
$18,500,000
Days On Site 
10 Days
Bedrooms 
4
Inside Area (SqFt) 
2,255 sqft
Total Baths 
5
Full Baths 
4
Partial Baths 
1
Lot Size 
0.34 Acres
Year Built 
1958
MLS® Number 
B26058354
Status 
Active
Property Tax 
$112,485
HOA/Condo/Coop Fees 
N/A
Sq Ft Source 
Public Records
Friends & Family
Recent Activity
2 weeks agoListing first seen on site
2 weeks agoListing updated with changes from the MLS®
General Features
Acres 
0.34
Carport 
2
Direction Faces 
East
Green Energy Efficient 
HVACAppliances
Levels 
One
Number Of Stories 
1
Parking 
Attached CarportCircular DrivewayCarportDriveway
Parking Spaces 
8
Pets 
Yes
Property Condition 
Updated/Remodeled
Property Sub Type 
Single Family Residence
Sewer 
Public Sewer
Special Circumstances 
Standard
SqFt Total 
3720
Utilities 
Electricity ConnectedSewer ConnectedWater Connected
Water Source 
Public
Zoning 
2001
Interior Features
Appliances 
CooktopDryerDishwasherENERGY STAR Qualified DishwasherENERGY STAR Qualified DryerENERGY STAR Qualified FreezerENERGY STAR Qualified RefrigeratorENERGY STAR Qualified WasherElectric CooktopElectric Water HeaterFree-Standing FreezerMicrowaveOvenRefrigeratorWater HeaterWine RefrigeratorWasher
Cooling 
Central Air
Flooring 
ConcreteLaminateTile
Furnished 
Unfurnished
Heating 
CentralElectric
Interior 
Entrance FoyerWalk-In Closet(s)
Laundry Features 
InsideLaundry RoomSink
Main Level Bedrooms 
4
Window Features 
Storm Window(s)
Dining Room 
Dimensions - 12 X 14Level - MainArea - 168
Kitchen 
Dimensions - 12 X 11Level - MainArea - 132
Living Room 
Dimensions - 16 X 22Level - MainArea - 352
PrimaryBedroom 
Dimensions - 25 X 20Level - MainArea - 500
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Exterior Features
Construction Details 
BrickConcrete
Exterior 
Garden
Frontage 
Waterfront
Lot Features 
GardenWaterfront
Patio And Porch 
CoveredPatio
Pool Features 
In GroundPrivate
Private Pool 
Yes
Roof 
Shingle
View 
WaterBayPool
Waterfront 
Yes
Waterfront Features 
BayfrontIntracoastal AccessNavigable WaterNo Fixed BridgesOcean AccessSeawall
Waterview 
WaterBayPool
Windows/Doors 
Storm Window(s)
Community Features
Financing Terms Available 
CashConventional
MLS Area 
2520
Schools
School District
Unknown
Elementary School
Key Biscayne K-8
Middle School
Ponce De Leon
High School
Coral Gables
Listing courtesy of Coldwell Banker



All listings featuring the BMLS logo are provided by BeachesMLS, Inc. This information is not verified for authenticity or accuracy and is not guaranteed. Copyright © 2026 BeachesMLS, Inc. (a Flex MLS feed)
Last checked: 2026-08-10 12:23 PM UTC

Neighborhood & Commute
Source: Walkscore
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