631 N Mashta DriveKey Biscayne, FL 33149MLS Number B26058354
- Price: $18,500,000
- Est. Mortgage of $/month
- 2 Days on Market
- 4Bedrooms
- 0.34Acreage
- 5Bathrooms
- 1958Year Built
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.
Listing by Coldwell Banker

Ocean Estate Properties
Office: 561-504-9226
500 NE Spanish River Boulevard
Suite 104
Boca Raton, FL 33431
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Tax Information
- Tax Legal Description MASHTA ISLAND PB 60-93 LOT 7 BLK 1 LOT SIZE 100.000 X 150 OR 17980-3315 0198 4
- Tax Year 2025
- Taxes$112,485
Basic Information
- List Price$18,500,000
- MLS NumberB26058354
- Modification Date07/31/2026
- Property SubTypeSingle Family Residence
- Property TypeResidential
- StatusACT
- Virtual TourView Tour
Interior
- Flooring Concrete, Laminate, Tile
- Furnished Unfurnished
Utilities
- Heat SystemCentral, Electric
- Heating YN Yes
- Utilities Electricity Connected, Sewer Connected, Water Connected
- Waste Water DisposalPublic Sewer
Water Body
- Water AccessPublic
- Water FeaturesBayfront, Intracoastal Access, Navigable Water, No Fixed Bridges, Ocean Access, Seawall
- WaterfrontYes
Legal
- Parcel Number 2452050080070
- Universal Parcel Id urn:reso:upi:2.0:US:12025:2452050080070
School Information
- Elementary SchoolKey Biscayne K-8
- High SchoolCoral Gables
- Junior HighPonce De Leon
Rooms
- Bathroom5
- Bedrooms4
- Full Bath4
- Half Baths1
- Laundry Features Inside, Laundry Room, Laundry Tub, Sink
- Main Level Bathrooms 4
- Main Level Bedrooms 4
Building
- Building ConstructionBrick, Concrete
- Rooms4
- Stories1
- Structure Type House
- Window Features Storm Window(s)
- Year Built1958
Amenities
- Appliances IncludedCooktop, Dryer, Dishwasher, ENERGY STAR Qualified Dishwasher, ENERGY STAR Qualified Dryer, ENERGY STAR Qualified Freezer, ENERGY STAR Qualified Refrigerator, ENERGY STAR Qualified Washer, Electric Cooktop, Electric Water Heater, Free-Standing Freezer, Microwave, Oven
- Cooling Central Air
- Cooling YN Yes
- Other Amenities
- Dock
- Garden
- Pool
- Tennis
- Water View
- Waterfront
- PetsNo Pet Restrictions, Yes
- Pool Features In Ground, Pool Equipment
- Pool Private YN Yes
Other
- Date Listed07/30/2026
- Green Energy Efficient HVAC, Appliances
- Green Verification YN Yes
- Possession Close Of Escrow, Negotiable
- Special Listing Conditions Standard
Parking
- Carport Spaces 2
- Carport YN Yes
- Open Parking Spaces 6
- Parking Features Attached Carport, Circular Driveway, Carport, Driveway
- Parking Total 8
Location
- Address631 N Mashta Drive
- Area2520
- Building Number631
- CountyMiami-Dade
- StateFL
- StreetN Mashta Drive
- SubdivisionMashta Island
- TownKey Biscayne
- Zip33149
Exterior
- Exterior Features Garden, Outdoor Living Area
- RoofShingle
Property Information
- Acreage0.34
- Frontage Length Remarks 100
- Frontage Type Waterfront
- Lot Features 1/4 to 1/2 Acre Lot, Sprinklers Automatic, Sprinkler System
- Occupant Type Vacant
- Patio And Porch Features Covered, Patio, Rooftop
- Property Condition Resale, Updated/Remodeled
- Property Sub Type Additional Single Family Residence
- Property View DescriptionBay, Intercoastal, Pool, Water
- Square Feet2,255
- View YN Yes
Based on information submitted to BeachesMLS as of July 31, 2026 7:42 AM UTC . All data is deemed reliable but is not guaranteed accurate by the MLS. All information should be independently reviewed and verified for accuracy. IDX information is provided exclusively for consumers’ personal, noncommercial use and may not be used for any purpose other than to identify prospective properties consumers may be interested in purchasing.
- Home
- Listings
- FL
- Miami-Dade
- Key Biscayne
- 33149
- 631 N Mashta Drive
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