Premier Brokers International
631 N Mashta Drive, Key Biscayne, FL 33149
ActiveBeachesMLS
ActiveMLS® B26058354
$18,500,000

631 N Mashta Drive, Key Biscayne, FL 33149

Beds
4
Baths
5
Sqft
2,255
Est. payment$114,616/mo
Home type
Single Family Residence
Year built
1958
Lot size
14,810 sqft
Price / sqft
$8,204
HOA
$0/mo
Community
MASHTA ISLAND

Property description

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 activity

Days on market
62
Listed
Jul 29, 2026
MLS listing updated
2 hours ago
Feed last checked
2 minutes ago

Listed by Javier Gustavo Quiroz · Coldwell Banker

Map

Map location is based on MLS-supplied coordinates. Verify the location before relying on it.

Facts & features

Interior

Bedrooms & bathrooms

Bedrooms
4
Bathrooms
5
Bathrooms (decimal)
4.5
Full bathrooms
4
Half bathrooms
1
Main-level bedrooms
4
Main-level bathrooms
4

Rooms & features

Rooms
4
Interior features
Entrance Foyer, Walk-In Closet(s)
Flooring
Concrete, Laminate, Tile
Appliances
Electric Water Heater, Wine Refrigerator, Electric Cooktop, Cooktop, Dishwasher, Dryer, ENERGY STAR Qualified Dishwasher, ENERGY STAR Qualified Dryer, ENERGY STAR Qualified Freezer, ENERGY STAR Qualified Refrigerator, ENERGY STAR Qualified Washer, Free-Standing Freezer, Microwave, Oven, Refrigerator, Washer, Water Heater
Laundry
Inside, Laundry Room, Sink
Fireplace
No
Furnished
Unfurnished
Window features
Storm Window(s)

Heating & cooling

Heating
Central, Electric
Cooling
Central Air
Property

Parking

Garage
No
Carport spaces
2
Carport
Yes
Parking spaces
8
Covered spaces
2
Parking features
Attached Carport, Carport, Circular Driveway, Driveway
Attached garage
No

Exterior

Stories
1
Building area
3,720 sqft
Patio & porch
Patio - Open, Patio - Covered, Patio
Exterior features
Garden, Private Rooftop Terrace
Pool
Yes
Pool features
Equipment Included, In Ground
View
Intracoastal, Bay, Pool, Water
Waterfront
No Fixed Bridge, Ocean Access, Bay, Intracoastal, Navigable Water, Seawall
Waterfront property
Yes

Lot

Lot size
14,810 sqft
Lot size (acres)
0.34 acres
Zoning
2001
Construction

Type & style

Home type
Single Family Residence
Structure type
House
Year built
1958
New construction
No

Materials

Construction
Brick, Concrete
Roof
Shingle
Property condition
Updated/Remodeled, Resale
Faces
East
Utilities & green energy

Utilities

Sewer
Public Sewer
Water
Public
Utilities
Electricity Connected, Sewer Connected, Water Connected
Green features
Appliances, HVAC
Community & HOA

Community

Subdivision
MASHTA ISLAND
MLS area
2520
MLS subarea
DADE
Pets allowed
No Restrictions, Yes
55+ community
No

Association

Has association
No
Estimated monthly dues
$0
Lease details

Not reported by the listing source.

Location

Area details

City
Key Biscayne
County
Miami-Dade
ZIP code
33149
Manufactured home details

Not reported by the listing source.

Financial & listing details

Listing

MLS number
B26058354
Possession
Close Of Escrow, Negotiable
Original list price
$18,500,000
Parcel number
2452050080070
Annual property tax
$112,485
Tax year
2025
Tax legal description
MASHTA ISLAND PB 60-93 LOT 7 BLK 1 LOT SIZE 100.000 X 150 OR 17980-3315 0198 4
Special listing conditions
Standard
Additional MLS details

Reported by the listing source

Association
No
Bathrooms Total Decimal
4.5
Bathrooms Total Integer
5
Building Area Total
3720
Construction Materials
Brick, Concrete
County Or Parish
Miami-Dade
Days On Market
62
Direction Faces
East
Elementary School
Key Biscayne K-8
Green Energy Efficient
Appliances, HVAC
High School
Coral Gables
Laundry Features
Inside, Laundry Room, Sink
List Price
18500000
Listing Contract Date
2026-07-29
Living Area
2255
Lot Size Acres
0.34
Lot Size Area
15000
MLSArea Major
2520
MLSArea Minor
DADE
Main Level Bathrooms
4
Main Level Bedrooms
4
Middle Or Junior School
Ponce De Leon
Mls Status
Active
On Market Date
2026-07-30
Parking Total
8
Patio And Porch Features
Patio - Open, Patio - Covered, Patio
Photos Count
49
Postal Code
33149
Property Sub Type
Single Family Residence
Property Type
Residential
Rooms Total
4
Senior Community
No
Standard Status
Active
State Or Province
FL
Status Change Timestamp
2026-07-30T18:40:52Z
Stories Total
1
Subdivision Name
MASHTA ISLAND
Water Source
Public
Waterfront Features
No Fixed Bridge, Ocean Access, Bay, Intracoastal, Navigable Water, Seawall
Tax Annual Amount
112485
Bathrooms Full
4
Pool Private
Yes
Bedrooms Total
4
Bathrooms Half
1

Market value

Automated estimate—No licensed valuation source connected
Estimated sales range—Ask Karim for a local market analysis
Estimated rent—No licensed rental valuation source connected

Price history

DateEventPrice
Jul 29, 2026ListedBeachesMLS$18,500,000$8,204/sqft

Public tax history

YearProperty taxesAssessment
2025$112,485—

Payment calculator

Estimated monthly payment$114,616/moIllustrative estimate, not a loan offer.
Principal & interest
$95,993
Property taxes
$9,374
Insurance
$9,250
Association dues
$0

Live national rate context is displayed below through Mortgage News Daily’s official widget. The calculator rate remains a separate assumption until licensed machine-readable access is connected. This is not a loan offer.

Neighborhood

Area

MASHTA ISLAND

Key Biscayne · Miami-Dade County · 33149

Climate risk

—

No licensed climate-risk source is connected.

Nearby schools

Key Biscayne K-8Elementary
—
Ponce De LeonMiddle
—
Coral GablesHigh
—
School names and districts are MLS-reported when available. Verify attendance boundaries with the school district. Ratings require a licensed ratings provider.

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BeachesMLS

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