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.
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
See this Listing
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
- Address520 S Mashta Dr Key Biscayne FL
- SubdivisionMASHTA ISLAND A REPLAT OF
- CityKey Biscayne
- CountyMiami-Dade County
- Zip Code33149
Subdivisions in Key Biscayne
- 101 CONDOMINIUM
- 150 SUNRISE DRIVE CONDO
- 155 SUNRISE CONDO
- 544-548 FERNWOOD CONDO
- BAHAMA HOUSE CONDO,Bahama House
- BAHAMA HOUSE SOUTH CONDO
- BAHAMA HOUSE SOUTH CONDO,KEY CASSA
- BAHIA MAR CONDO OF KEY BI
- Beach Haus Key Biscayne,Beach Haus
- BISC KEY ESTATES
- BISCAYNE KEY ESTATES
- BLUE PELICAN CONDO
- CAPE FLA CLUB CONDO CLUST
- CAPE FLA SUB SEC 2
- CAPE FLORIDA CLIB CONDO P
- CAPE FLORIDA CLUB CONDO P
- CAPE FLORIDA SUB SEC 1
- CAPE FLORIDA SUB SEC 3
- CAPE FLORIDA SUB SEC 3,Village Estate
- CASA DEL MAR
- CASA DEL MAR CONDO
- CAY POLYNESIA CONDO
- CLUB TOWER ONE CONDO
- CLUB TOWER THREE CONDO
- CLUB TOWER THREE CONDO,CLUB TOWER THREE CON
- CLUB TOWER TWO CONDO
- commodore club
- COMMODORE CLUB SOUTH COND
- COMMODORE CLUB SOUTH COND,COMMODORE
- COMMODORE CLUB SOUTH COND,COMMODORE CLUB SOUTH
- Commodore Club South Condo
- COMMODORE CLUB WEST CONDO
- COMMODORE CLUB WEST CONDO,COMMODORE CLUB
- CRANDON TOWER CONDO
- G B RESORT CONDO HOTEL
- G B Resort Condo Hotel,Ritz Carlton
- G B VILLAS
- GALEN 250 CONDO
- GALEN DRIVE CONDO APTS
- GALEN DRIVE WEST CONDOMIN
- GRAND BAY RESIDENCES COND
- GRAND BAY RESIDENCES COND,GRAND BAY
- GRAND BAY TOWER CONDO
- GRAND BAY TOWER CONDO,GRAND BAY
- GRAND BAY TOWER CONDO,GRAND BAY TOWER COND
- GRAPETREE TOWNHOUSE CONDO
- HOLIDAY COLONY
- INDIES CONDO
- ISLAND BREAKERS CONDO
- ISLAND HOUSE
- ISLAND HOUSE APT INC – CO
- KEY BISC AMBASSADOR CONDO
- KEY BISC AMBASSADOR CONDO,Key Biscayne Ambassa
- Key Biscayne Ambassador Co
- KEY BISCAYNE COMMODORE CL
- KEY BISCAYNE COMMODORE CL,Commodore
- KEY BISCAYNE ONE HUNDRED
- KEY BISCAYNE VI CONDO
- KEY BISCAYNE VI CONDO,KEY BISCAYNE VI COND
- KEY BISCAYNE VI CONDO,KEY BISCAYNE VICONDO
- KEY BISCAYNES COMMODORE C
- Key Cassa
- KEY COLONY
- KEY COLONY CONDO #4,KEY COLONY CONDO 4
- Key Colony Condo 01,KEY COLONY NO 1
- Key Colony I
- KEY COLONY NO 1
- KEY COLONY NO 1,KEY COLONY
- Key Colony No 1,Key Colony-Tidemark
- KEY COLONY NO 1,Tidemark
- KEY COLONY NO 1,TIDEMARK KEY COLONY
- Key Colony No 2
- KEY COLONY NO 2 CONDO
- KEY COLONY NO 2 CONDO,KEY COLONY NO 2 COND
- KEY COLONY NO 2 CONDO,Oceansoun
- KEY COLONY NO 4 CONDO
- KEY COLONY NO 4 CONDO,Key Colony
- KEY COLONY NO 4 CONDO,Key Colony Botanica
- KEY COLONY NO 4 CONDO,KEY COLONY NO 4 COND
- KEY ISLANDER CONDO
- Key Islander Condo,Key Islander condo
- LAKE TOWER CONDO
- LAKE VILLA ONE CONDO
- LAKE VILLA ONE CONDO,The Ocean Club
- LAKE VILLA THREE CONDO
- LAKE VILLA TWO CONDO
- Le Phare Condo,Le phare
- LE PHARE KEY BISCAYNE CON
- LE PHARE KEY BISCAYNE CON,Le Phare
- LE PHARE KEY BISCAYNE CON,LE PHARE KEY BISCAYN
- MAR-AZUL CONDO
- MASHTA ISLAND
- MASHTA ISLAND A REPLAT OF
- MATHESON ESTATES
- MATHESON ESTATES,MATHESON STATES
- NORTH SUNRISE INC CONDO
- OCEAN LANE PLAZA CONDO
- Ocean Tower 2,Ocean Club
- OCEAN TOWER ONE CONDO
- OCEAN TOWER ONE CONDO
- OCEAN TOWER ONE CONDO,Ocean Club
- OCEAN TOWER ONE CONDO,OCEAN TOWER ONE COND
- OCEAN TOWER TWO CONDO
- OCEAN TOWER TWO CONDO,OCEAN TOWER TWO COND
- OCEAN VILLAGE CONDO
- OCEAN VILLAGE CONDO,OCEAN VILLAGE
- OCEAN VILLAGE CONDO,Ocean Village Condo
- Oceana Key Biscayne
- OCEANA KEY BISCAYNE CONDO
- OCEANA KEY BISCAYNE CONDO,OCEANA
- OCEANA KEY BISCAYNE CONDO,OCEANA KEY BISCAYNE
- Oceansound Phase II
- RESORT VILLA ONE CONDO
- RESORT VILLA ONE CONDO,Resort Villa One
- RESORT VILLA ONE CONDO,RESORT VILLA ONE CON
- RESORT VILLA TWO CONDO
- SANDS OF KEY BISCAYNE CON
- SANDS OF KEY BISCAYNE CON,SANDS OF KEY BISCAYN
- SANDS OF KEY BISCAYNE,SANDS OF KEY BISCAYN
- SMUGGLERS COVE
- SOLIMAR CONDO OF KEY BISC
- SOLIMAR CONDO OF KEY BISC,SOLIMAR CONDO
- SUNRISE CLUB CONDO
- SUNRISE CLUB CONDO,100 SUNRISE
- SUNRISE MANOR CONDO
- THE EMERALD BAY
- THE EMERALD BAY Key Colony
- THE EMERALDBAY
- THE EMERALDBAY @ KEY COLO
- THE EMERALDBAY @ KEY COLO,KEY COLONY
- THE EMERALDBAY @ KEY COLO,THE EMERALD BAY
- THE EMERALDBAY @ KEY COLON
- THE EMERALDBAY KEY COLONY
- The Ocean Club
- THE PALMS OF KEY BISCAYNE
- THE PYRAMIDS @ KEY BISCAY
- TIDEMARK KEY COLONY NO 1,Key Colony
- Tidemark,Key Colony
- TOWERS OF KEY BISCAYNE CO
- TOWERS OF KEY BISCAYNE CO,The Towers of Key Bi
- TOWERS OF KEY BISCAYNE CO,TOWERS OF KEY BISCAY
- TOWERS OF KEY BISCAYNE CON
- TROPICAL ISLE HOMES SUB
- TROPICAL ISLE HOMES SUB 1
- TROPICAL ISLE HOMES SUB 2N
- TROPICAL ISLE HOMES SUB 3
- TROPICAL ISLE HOMES SUB 3,TROPICAL ISLE HOMES
- TROPICAL ISLE HOMES SUB 4
- VILLAHARBOUR APTS CONDO
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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