How much is 520 S Mashta Drive?

520 S Mashta Drive is listed at $18,500,000, which is about $5,997 per square foot. The listing page shows comparable active listings and recent closed sales nearby so you can judge the asking price against what buyers have actually paid.

What are the property taxes on 520 S Mashta Drive?

The listing reports annual property taxes of $201,741 for 2026. Taxes are reassessed at the sale price after a purchase, so a new owner's bill can differ from the current owner's; use the mortgage calculator on this page for an estimate.

When was 520 S Mashta Drive built?

520 S Mashta Drive was built in 1961 and the listing describes its condition as resale. Age matters for insurance and financing in Florida: ask about the roof, the electrical panel and, for a condo built before the current code, the building's structural reserve study.

How long has 520 S Mashta Drive been on the market?

520 S Mashta Drive has been listed for 88 days, and the asking price has been reduced from $19,900,000. Days on market and price changes are the first signals of how much room there is to negotiate.

Is 520 S Mashta Drive waterfront?

Yes. The listing describes the water as ocean access seawall bayfront. For a home with dockage, confirm the water depth at low tide, the seawall condition and whether the route to the inlet passes under any fixed bridges before you offer.

Which schools serve 520 S Mashta Drive?

The MLS lists Key Biscayne K-8 (elementary), Ponce De Leon (middle), Coral Gables (high). School assignments are set by the district and can change; verify them with the school board before you rely on them.

How do I see 520 S Mashta Drive?

Request a showing from this page or call BreakThru Realty and a licensed agent will arrange a private tour, in person or by video, and answer anything the listing leaves out.

520 S Mashta Drive, Key Biscayne, FL 33149

$18,500,000 · Active

5 beds
4 baths
3,085 sq ft
88 days on market
Single Family Residence
Built 1961
Lot 22,215.6 sq ft
4,177 sq ft total
2 garage spaces
Miami-Dade County
MLS# A12071221
Mashta Island A Replat Of

Photo 1 at 520 S Mashta Drive, Key Biscayne

Photo 2 at 520 S Mashta Drive, Key Biscayne

Photo 3 at 520 S Mashta Drive, Key Biscayne

Photo 4 at 520 S Mashta Drive, Key Biscayne

Photo 5 at 520 S Mashta Drive, Key Biscayne

Photo 6 at 520 S Mashta Drive, Key Biscayne

Photo 7 at 520 S Mashta Drive, Key Biscayne

Photo 8 at 520 S Mashta Drive, Key Biscayne

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.

Features

Bedroom Layout - Split
Ocean Access
Seawall
Bayfront
In Ground

Schools

Elementary: Key Biscayne K-8
Middle: Ponce De Leon
High: Coral Gables

Presented by

BreakThru Realty · (786) 914-1017

Courtesy of

Coldwell Banker Realty · michaelj.suarez@cbrealty.com · Listing agent: Maureen Jauregui

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 not be used for any purpose other than to identify prospective properties consumers may be interested in purchasing. Data is deemed reliable but is not guaranteed accurate by BeachesMLS. Listings held by brokerage firms other than BreakThru Realty carry the name of the listing broker.

Schedule a showing

Call or text BreakThru Realty at (786) 914-1017 or email sales@breakthrurealty.com to see 520 S Mashta Drive.

Before You Make an Offer

Buying a waterfront home: ocean access, bridges and docks

How buying a home in South Florida works

Your Waterfront Buyer May Already Be Working With Us

BreakThru Realty works with buyers searching for waterfront homes with ocean access, no fixed bridges, deep water, private docks and Intracoastal frontage. Boaters know the vessel they need to keep behind the house, and they tell us. If you own a waterfront home, a broker can compare its frontage, dock and route to the ocean with those requirements and discuss a potential buyer match before you list.

BreakThru Realty works with hundreds of prequalified buyers searching for properties. Before you list, a broker reviews what you own, the market around it and whether an existing buyer's requirements match. If none does, you see how we would position it to reach other qualified buyers.

Find Out If We Have Your Buyer · Discuss Selling With BreakThru Realty

A potential match is a conversation, not an offer, until the buyer sees your property and makes one. No buyer is named and nothing about your property or business is shared until you decide to proceed.

Questions About 520 S Mashta Drive

How much is 520 S Mashta Drive?: 520 S Mashta Drive is listed at $18,500,000, which is about $5,997 per square foot. The listing page shows comparable active listings and recent closed sales nearby so you can judge the asking price against what buyers have actually paid.
What are the property taxes on 520 S Mashta Drive?: The listing reports annual property taxes of $201,741 for 2026. Taxes are reassessed at the sale price after a purchase, so a new owner's bill can differ from the current owner's; use the mortgage calculator on this page for an estimate.
When was 520 S Mashta Drive built?: 520 S Mashta Drive was built in 1961 and the listing describes its condition as resale. Age matters for insurance and financing in Florida: ask about the roof, the electrical panel and, for a condo built before the current code, the building's structural reserve study.
How long has 520 S Mashta Drive been on the market?: 520 S Mashta Drive has been listed for 88 days, and the asking price has been reduced from $19,900,000. Days on market and price changes are the first signals of how much room there is to negotiate.
Is 520 S Mashta Drive waterfront?: Yes. The listing describes the water as ocean access seawall bayfront. For a home with dockage, confirm the water depth at low tide, the seawall condition and whether the route to the inlet passes under any fixed bridges before you offer.
Which schools serve 520 S Mashta Drive?: The MLS lists Key Biscayne K-8 (elementary), Ponce De Leon (middle), Coral Gables (high). School assignments are set by the district and can change; verify them with the school board before you rely on them.
How do I see 520 S Mashta Drive?: Request a showing from this page or call BreakThru Realty and a licensed agent will arrange a private tour, in person or by video, and answer anything the listing leaves out.
To request a tour, call (786) 914-1017 or email sales@breakthrurealty.com.

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Recently Sold Nearby

591 N Mashta Drive, Key Biscayne, FL 33149 · Sold $14,000,000 · 4 bd · 4.5 ba · 4,290 sq ft

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Nearby ZIP Codes

The 4 bedroom home at 631 N Mashta Drive, Key Biscayne, FL 33149 is comparable and listed for sale at $18,500,000. Another comparable home, 591 N Mashta Drive, Key Biscayne, FL 33149, sold for $14,000,000 in August 2026. Key Biscayne neighborhoods include Commodore Club and Ocean Club. Nearby ZIP codes include 33133 and 33131. This property also neighbors Coconut Grove, Brickell, and Miami. Compare it with the Key Biscayne housing market report.