520 S Mashta Dr

Key Biscayne, FL
$ 19,900,000 Beds 5 Baths 4 Sq 3,085 Virtual Tour
Monthly Estimate* How much can I afford?

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.

Active

  • Price
  • $ 19,900,000
  • City
  • Key Biscayne
  • Bedrooms
  • 5
  • Full Bathrooms
  • 4
  • County
  • Miami-Dade
  • Half Bathrooms
  • 0
  • Area
  • 52
  • Lot Size
  • Zip
  • 33149
  • Sqr Footage
  • 3,085
  • Year Built
  • 1961
  • Taxes
  • $ 201741
  • Style
  • MLS#
  • A12071221
Listed By: This listing is courtesy of Coldwell Banker Realty
Data Source: Southeast Florida MLS (SEFMLS)

Features

General

Sewer Public Sewer
Heating Central
Cooling Central Air
Possession Closing & Funding
Roof Barrel,Spanish Tile
Appliances Other
Garage Spaces 2
Architectural Style One Story
Pool Features In Ground,Pool
Restrictions OK To Lease
Construction Materials Block
Year Built 1961
View Bay,Ocean
Stories Count 1
Property Subtype Single Family Residence
Tax Year 2026
Waterfront Features Bayfront,Ocean Access,Seawall
Community Features Other,See Remarks
County Miami-Dade
Property Type Residential
Subdivision Name MASHTA ISLAND A REPLAT OF
Facing Direction East
Garage Y/N true
Full Baths 4
Special Listing Conditions Listed As-Is
Status Active
High School Coral Gables
City Key Biscayne
Disclosures None
Senior Community Y/N false
Zoning Description 2001
MLS Area 52
Lot Size Units Square Feet
Lot Size Square Feet 22140
Listing Terms Cash,Conventional
Elementary School Keybiscayne
Year Built Details Resale
Tax Annual Amount 201741
Middle/Junior High School Ponce De Leon
Lease Considered Y/N false
Virtual Tour https://www.propertypanorama.com/instaview/mia/A12071221
Standard Status Active
Occupancy Type Call Agent
Property Sub Type Additional Single Family Residence
PostalCity Key Biscayne
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

Interior Features

Interior Amenities Bedroom on Main Level,First Floor Entry,Split Bedrooms
Flooring Tile
Air Conditioning Y/N true
Heating Y/N true
Total Bedrooms 5
Total Baths 4

Exterior Features

Exterior Amenities Security/High Impact Doors
Parking Features Driveway
Water Source Public
Lot Size Area 22140
Building Area Total 4177
Frontage Length 138
Private Pool true
Waterfront Y/N true
Covered Spaces 2

Amenities

  • Foreclosure
  • Views
  • Short Sale
  • New Construction
  • Adult 55+
  • Lease To Own
  • No HOA Fees
  • Furnished
  • Primary On Main
  • Air Conditioning
  • Seller Finance
  • Green
  • Fixer Upper
  • Horse
  • Golf
  • Fireplace
  • Deck
  • Garage
  • Basement
  • Pool

Affordability Calculator

$3,786

Per Month

Based on the average sale price from the Miami Beach, FL office

  • Monthly Principal & interest $2,658
  • Monthly Property Taxes $1,062
  • Monthly Home Insurance $67
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Let's determine your purchasing power. Working with my mortgage partner, you'll have the information you need to shop for a home with confidence.

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.

Mortgage calculator provided courtesy of Inside Real Estate.

Schools

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

Price History

8/17/2026 Listed $19,900,000

Property vs Zip Code Average in 33149

Price
AVG $9.24M
$19.9M
Taxes
AVG $76,969
$201,741
Year Built
AVG 1986
1961

In The Neighborhood

Areas That We Cover

520 S Mashta Dr Key Biscayne, FL is a Single Family Home for sale at $19900000 with 3085 sqft and a lot size of Acre(s). 520 S Mashta Dr Key Biscayne has 5 bedrooms, 4 baths and was built in 1961. The property's zip code is 33149 which is in Key Biscayne, FL

*Information deemed reliable but not guaranteed.

Financial calculator disclaimer: 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.

Mortgage calculator provided courtesy of Inside Real Estate.

All information deemed reliable, but not guaranteed, and should be independently verified. The real estate information and related content displayed on this site is provided for consumers personal, non-commercial use and may not be used for any purpose other than to identify prospective properties consumers may be interested in purchasing.

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Joel Arguello

305-384-6502

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