631 N Mashta Drive Key Biscayne, FL $ 18,500,000
631 N Mashta Drive
$ 18,500,000
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631 N Mashta Drive

Key Biscayne, FL, 33149
$ 18,500,000
Bedrooms4 Baths4.1 Sq 2,255

Monthly Estimate*

$ 116,811

631 N Mashta Drive, Key Biscayne, FL 33149 - Image 1
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631 N Mashta Drive, Key Biscayne, FL 33149 - Image 3
631 N Mashta Drive, Key Biscayne, FL 33149 - Image 4
631 N Mashta Drive, Key Biscayne, FL 33149 - Image 5
631 N Mashta Drive, Key Biscayne, FL 33149 - Image 6
631 N Mashta Drive, Key Biscayne, FL 33149 - Image 7
631 N Mashta Drive, Key Biscayne, FL 33149 - Image 8
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Single Family Home for sale in Key Biscayne, FL

for $18,500,000 with 4 bedrooms and 4 full baths, 1 half bath. This 2,255 square foot home was built in 1958 on a lot size of 0.34.

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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Single Family Active

Price

$ 18,500,000

Bedrooms

4

Full Bath

4

Half Bath

1

Property Type

Single Family

Taxes

$ 112,485

Style

Lot Size

0.34

Year Built

1958

Town/City

Key Biscayne

County/Region

Miami-Dade

MLS | Web ID

B26058354

Features
General
Membership Required false
Membership Description No Membership Available
Sewer Public Sewer
Heating Central Electric
Cooling Central Air
Utilities Electricity Connected Sewer Connected Water Connected
Possession Close Of Escrow Negotiable
Roof Shingle
Appliances Cooktop 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 Refrigerator Water Heater Wine Refrigerator Washer
Patio/Porch Features Covered Patio Rooftop
Pool Features In Ground Pool Equipment
Construction Materials Brick Concrete
Pets Allowed No Pet Restrictions Yes
Year Built 1958
View Bay Intercoastal Pool Water
Stories Count 1
Levels One
Property Subtype Single Family Residence
Tax Year 2025
Waterfront Features Bayfront Intracoastal Access Navigable Water No Fixed Bridges Ocean Access Seawall
Accessibility None
County Miami-Dade
New Construction false
Property Type Residential
Energy Efficient HVAC Appliances
Subdivision Name MASHTA ISLAND
Facing Direction East
Garage Y/N false
Total Rooms 4
Full Baths 4
Status Active
High School Coral Gables
City Key Biscayne
Senior Community Y/N false
MLS Area 2520
Carport Spaces 2
Carport Y/N true
Elementary School Key Biscayne K-8
Tax Annual Amount 112485
Middle/Junior High School Ponce De Leon
Property Condition Resale Updated/Remodeled
Virtual Tour https://www.propertypanorama.com/631-N-Mashta-Drive-Key-Biscayne-FL-33149/unbranded
Standard Status Active
Occupancy Type Vacant
Property Sub Type Additional Single Family Residence
Legal Description MASHTA ISLAND PB 60-93 LOT 7 BLK 1 LOT SIZE 100.000 X 150 OR 17980-3315 0198 4
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Interior
Interior Amenities Dual Sinks Entrance Foyer Living/Dining Room Walk-In Closet(s)
Flooring Concrete Laminate Tile
Furnished Y/N Unfurnished
Total Stories 1
Air Conditioning Y/N true
Heating Y/N true
Window Features Storm Window(s)
Fireplace Y/N false
Half Baths 1
Laundry Features Inside Laundry Room Laundry Tub Sink
Total Bedrooms 4
Main Level Bedrooms 4
Main Level Bathrooms 4
Total Baths 5
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Exterior
Exterior Amenities Garden Outdoor Living Area
Parking Features Attached Carport Circular Driveway Carport Driveway
Lot Features 1/4 to 1/2 Acre Lot Sprinklers Automatic Sprinkler System
Water Source Public
Total Parking 8
Lot Size Area 15000
Building Area Total 3720
Lot Size Acres 0.34
Frontage Length 100.00
Frontage Type Waterfront
Waterfront Y/N true
Covered Spaces 2
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* Excluded Features
List By
Javier Gustavo Quiroz

Listing Agent

Affordability Calculator

$126,185
Per Month
93%
7%
0%
Monthly Principal & Interest
$116,811
Monthly Property Taxes
$9,374
Monthly Home Insurance
--
Default based on a 30-year fixed rate of 6.49% with 20% down. The estimated payment is offered for convenience and is not an offer of credit. Due to market fluctuations, interest rates are subject to change at any time and without notice. Your individual rate may vary. Rates may differ for FHA, VA or jumbo loans.
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Nearby
0 Elementary School
4268812 Middle School
Coral Gables High School High School
Pricing History
DatePricePrice ChangeDescription
7/30/2026$18,500,000 Listed Price

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631 N Mashta Drive, Key Biscayne, FL, 33149 is a Single Family Home for sale at $18,500,000 with 2,255 sqft and a lot size of 0.34. 631 N Mashta Drive has 4 bedrooms, 4.1 baths, and was built in 1958. The property's zip code is 33149 which is in Key Biscayne, FL