Premier Brokers International
520 S Mashta Drive, Key Biscayne, FL 33149
Price reducedMLS listing sourceMIAMI REALTORS® MLS
Price reducedMLS® A12071221
$18,500,000

↓ Price reduced $1,400,000 on Oct 23, 2026

520 S Mashta Drive, Key Biscayne, FL 33149

Beds
5
Baths
4
Sqft
3,085
Est. payment$122,054/mo
Home type
Single Family Residence
Year built
1961
Lot size
22,216 sqft
Price / sqft
$5,997
HOA
$0/mo
Community
MASHTA ISLAND A REPLAT OF

Property description

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.

Listing activity

Days on market
78
Listed
Aug 12, 2026
MLS listing updated
Oct 29, 2026
Feed last checked
8 minutes ago

Listed by Maureen Jauregui · Coldwell Banker Realty

Map

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

Facts & features

Interior

Bedrooms & bathrooms

Bedrooms
5
Bathrooms
4
Bathrooms (decimal)
4
Full bathrooms
4
Half bathrooms
0

Rooms & features

Rooms
1
Interior features
Bedroom Layout - Split
Flooring
Tile
Appliances
Other
Other equipment
Other

Heating & cooling

Heating
Central
Cooling
Central Air
Property

Parking

Garage spaces
2
Garage
Yes
Covered spaces
2
Parking features
Driveway
Attached garage
No

Exterior

Stories
1
Building area
4,177 sqft
Entry level
1
Pool
Yes
Pool features
In Ground
View
Direct Ocean, Bay
Waterfront
Ocean Access, Bay, Seawall
Waterfront property
Yes

Lot

Lot size
22,216 sqft
Lot size (acres)
0.51 acres
Zoning
2001
Construction

Type & style

Home type
Single Family Residence
Year built
1961
New construction
No

Materials

Construction
Block
Roof
Barrel, Spanish Tile
Property condition
Resale
Levels
One
Faces
East
Utilities & green energy

Utilities

Sewer
Public Sewer
Water
Public
Community & HOA

Community

Subdivision
MASHTA ISLAND A REPLAT OF
MLS area
2520
55+ community
No

Association

Has association
No
Estimated monthly dues
$0
Amenities
Other
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
A12071221
Possession
Negotiable
Original list price
$19,900,000
Parcel number
2452050090170
Annual property tax
$201,741
Tax year
2026
Tax legal description
5-6 55 42 MASHTA ISLAND A REPLAT OF TRS A & C SELY35FT LOT 16 & ALL LT 17 BLK BLK 3 LOT SIZE 135.000 X 164 OR 15816-1278 1292 1
Additional MLS details

Reported by the listing source

Association Amenities
Other
Association
No
Bathrooms Total Decimal
4
Bathrooms Total Integer
4
Building Area Total
4177
Construction Materials
Block
County Or Parish
Miami-Dade
Days On Market
78
Direction Faces
East
Elementary School
Key Biscayne K-8
High School
Coral Gables
List Price
18500000
Listing Contract Date
2026-08-12
Living Area
3085
Lot Size Acres
0.51
Lot Size Area
22140
MLSArea Major
2520
Middle Or Junior School
Ponce De Leon
Mls Status
Active
On Market Date
2026-08-12
Photos Count
38
Postal Code
33149
Price Change Timestamp
2026-10-23T18:08:11Z
Property Sub Type
Single Family Residence
Property Type
Residential
Rooms Total
1
Senior Community
No
Standard Status
Active
State Or Province
FL
Status Change Timestamp
2026-08-12T04:00:00Z
Stories Total
1
Subdivision Name
MASHTA ISLAND A REPLAT OF
Water Source
Public
Waterfront Features
Ocean Access, Bay, Seawall
Tax Annual Amount
201741
Bathrooms Full
4
Pool Private
Yes
Bedrooms Total
5
Bathrooms Half
0

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
Aug 12, 2026ListedMIAMI REALTORS® MLS$19,900,000$6,451/sqft
Oct 23, 2026Price reducedMIAMI REALTORS® MLS$18,500,000$5,997/sqft

Public tax history

YearProperty taxesAssessment
2026$201,741—

Payment calculator

Estimated monthly payment$122,054/moIllustrative estimate, not a loan offer.
Principal & interest
$95,993
Property taxes
$16,812
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 A REPLAT OF

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.

Nearby homes

12 homes

Similar homes

12 homes
MLS listing source

MIAMI REALTORS® MLS · Listing courtesy of Coldwell Banker Realty. All listings featuring the BMLS logo are provided by BeachesMLS, Inc. This information is not verified for authenticity or accuracy and is not guaranteed. Copyright ©2026 BeachesMLS, Inc. IDX information is provided exclusively for consumers’ personal, non-commercial use and may be used only to identify prospective properties they may be interested in purchasing or leasing. Terms of use · Equal Housing Opportunity.