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5 Beds
4 Baths
3,085 sqft

$19,900,000

520 S Mashta Dr, Key Biscayne FL, 33149

Price per sqft$6,450.57
Built in1961
Property size3,085 sqft
Property typeResidential

Overview

Active

Listed Aug 12, 2026

Updated 2 weeks ago

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.

$132,395/mo

Est. mortgage payment based on a $19,900,000 home price.

All estimates are provided by Luxury Presence for informational purposes only. Actual amounts may vary.

Additional information

MLS® ID
A12071221

Interior Features

Bedrooms
5
Bathrooms
4
Cooling
Yes
Heating
Yes
Basement
No

Exterior Features

Lot Size
0.51 Acres

Other Property Details

Taxes
$201,741
Tax Frequency
Annually
Garage
Yes
View
Yes
Pool
Yes
Waterfront
Yes
MLS provider logo

Based on information from the Miami Association of REALTORS®. This information is for your personal, non-commercial use and may not be used for any purpose other than to identify prospective properties you may be interested in purchasing. Display of MLS data is usually deemed reliable but is NOT guaranteed accurate by the MLS.  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. Unless otherwise specified in writing, Broker/Agent has not and will not verify any information obtained from other sources. The Broker/Agent providing the information contained herein may or may not have been the Listing and/or Selling Agent. The listing broker’s offer of compensation is made only to participants of the MLS where the listing is filed. 

©2026 Miami Association of REALTORS® all rights reserved. 

Data last updated 3:04 AM UTC, 8/28/2026.

Listed by:  Coldwell Banker Realty, 305-361-5722

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