Single-family home for sale

$18,500,000

520 S Mashta DrKey Biscayne, FL 33149

  • 5 Beds
  • 4 Baths
  • 3,085 Sq ft
  • 22,140 Lot sq ft
  • 1961 Built

About this home

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.

Details

MLS #
A12071221
Property type
Single-family home
Status
Active
Days on market
72
Neighborhood
MASHTA ISLAND A REPLAT OF
County
Miami-Dade County
Property taxes
$201,741 (2026)
Waterfront
Yes
Private pool
No
View
Bay, Direct Ocean
Garage spaces
2
Cooling
Central Air
Interior features
First Floor Entry, Split Bedroom, Family Room
Appliances
Other Equipment/Appliances

Location

Estimated payment

$110,358/mo with 20% down at 6.5% for 30 years, including taxes, before insurance.

Adjust in the mortgage calculator

Listing courtesy of Coldwell Banker Realty · Maureen Jauregui. Listing last updated October 23, 2026 1:08 PM.

REALTOR® and MLS logo

The multiple listing information is provided by the MIAMI Association of REALTORS® from a copyrighted compilation of listings. The compilation of listings and each individual listing are © 2026 MIAMI Association of REALTORS®. All rights reserved. The information provided is for consumers' personal, noncommercial use and may not be used for any purpose other than to identify prospective properties consumers may be interested in purchasing. All properties are subject to prior sale or withdrawal. All information provided is deemed reliable but is not guaranteed accurate, and should be independently verified. Data last updated October 26, 2026 10:10 AM.

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