520 S Mashta Dr Key Biscayne FL 33149 | MLS #A12071221

520 S Mashta Dr
Key Biscayne, FL, 33149
$19,900,000
5 Beds
4 Baths
3,085 SqFt
0 Acres
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MLS #A12071221 image #0
Seize a rare opportunity to create a landmark waterfront estate on one of the largest residential lots in Key Biscayne’s exclusive Mashta Island enclave. Spanning an extraordinary 22,140 square feet, this exceptional property offers 138 feet of pristine water frontage and sweeping open water views, providing an unparalleled setting for a world class residence.
Plans by renowned architect, Pablo Corazzini of Vitalini Corazzini Architects, are available to the buyer, offering a thoughtfully conceived vision that takes full advantage of the property’s remarkable scale, premier waterfront setting, and spectacular sunsets. The proposed design creates an extraordinary canvas for sophisticated indoor-outdoor living and entertaining, should the buyer choose to pursue the concept.
With its exceptional lot size, expansive water frontage, and coveted Mashta Island address, this is a truly irreplaceable opportunity to create a legacy estate in one of South Florida’s most prestigious waterfront communities.

Property Details

Price:
$19,900,000
MLS #:
A12071221
Status:
Active
Beds:
5
Baths:
4
Type:
Single Family
Subtype:
Single Family Residence
Subdivision:
MASHTA ISLAND A REPLAT OF
Neighborhood:
mashtaislandareplatof
Listed Date:
Aug 12, 2026
Finished Sq Ft:
3,085
Total Sq Ft:
4,177
Year Built:
1961
WaterfrontPoolMashta Island A Replat OfMashtaislandareplatofMashta Island A Replat OfKeybiscaynePonce De LeonCoral GablesOk To Lease

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Schools

Elementary School:
Keybiscayne
Middle School:
Ponce De Leon
High School:
Coral Gables

Interior

Appliances
Other Equipment/Appliances
Bathrooms
4 Full Bathrooms
Cooling
Central Air
Flooring
Tile
Heating
Central
Interior Features
First Floor Entry, Split Bedroom, Family Room

Exterior

Architectural Style
Attached, One Story
Community Features
Other Subdivision – See Remarks
Construction Materials
Concrete Block Construction
Covered Spaces
2
Direction Faces
East
Garage Spaces
2
Lot Features
1/2 To Less Than 3/4 Acre Lot
Open Parking YN
1
Parking Features
Driveway
Roof
Barrel Roof, Curved/S-Tile Roof
View
Bay, Direct Ocean
Waterfront Features
Ocean Access, Seawall

Financial

Tax Year
2026
Taxes
$201,741

Map

Community

Subdivisions in Key Biscayne

Market Summary

Current real estate data for Single Family in Key Biscayne as of Sep 03, 2026
43
Single Family Listed
167
Avg DOM
2,809
Avg $ / SqFt
$14,847,930
Avg List Price

Property Summary

    Located in the MASHTA ISLAND A REPLAT OF subdivision, 520 S Mashta Dr Key Biscayne FL is a Single Family for sale in Key Biscayne, FL, 33149. It is listed for $19,900,000 and features 5 beds, 4 baths, and has approximately 3,085 square feet of living space, and was originally constructed in 1961. The current price per square foot is $6,451. The average price per square foot for Single Family listings in Key Biscayne is $2,809. The average listing price for Single Family in Key Biscayne is $14,847,930. To schedule a showing of MLS#a12071221 at 520 S Mashta Dr in Key Biscayne, FL, contact your CENTURY 21 Carioti agent at 2392986550.

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Key Biscayne, FL