How do I schedule a tour of 520 S Mashta Drive, Key Biscayne, FL 33149?

Use the Tour button on this listing to request a showing of 520 S Mashta Drive, Key Biscayne, FL 33149. Pick a day and time and choose an in-person or video-chat tour, and a Pure Equity Realty agent will confirm your visit, often the same day.

Is 520 S Mashta Drive, Key Biscayne, FL 33149 still available?

520 S Mashta Drive, Key Biscayne, FL 33149 is currently listed as Active, and has been on the market 15 days. Status updates directly from the MLS as homes go under contract, so ask us to confirm availability before you plan a visit.

How much is the monthly payment for 520 S Mashta Drive, Key Biscayne, FL 33149?

With 20% down ($3,980,000) on the $19,900,000 list price and a 30-year fixed loan at an illustrative 6.875% rate, the estimated principal & interest for 520 S Mashta Drive, Key Biscayne, FL 33149 is about $104,583/mo, before property taxes, insurance. Use the payment estimate on this page to adjust the down payment and rate.

How do I get pre-approved to buy 520 S Mashta Drive, Key Biscayne, FL 33149?

Getting pre-approved shows sellers you're a serious buyer and clarifies your true budget before you offer on 520 S Mashta Drive, Key Biscayne, FL 33149. Contact Pure Equity Realty and we'll connect you with a trusted local lender to review your financing options, no obligation.

What schools serve 520 S Mashta Drive, Key Biscayne, FL 33149?

520 S Mashta Drive, Key Biscayne, FL 33149 is zoned for Key Biscayne K-8 (elementary), Ponce De Leon (middle), Coral Gables (high). School assignments and boundaries can change year to year, so confirm current zoning with the local school district before you buy.

Can I negotiate the price of 520 S Mashta Drive, Key Biscayne, FL 33149?

Often, yes. The right offer on 520 S Mashta Drive, Key Biscayne, FL 33149 depends on how it's priced against comparable single family sales in Key Biscayne, how long it's been listed, and how motivated the seller is. Pure Equity Realty will run the comps and help you craft a competitive, well-supported offer.

Active

15 Days on Market

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$19,900,000

520 S Mashta Drive

Key Biscayne, FL 33149

MASHTA ISLAND A REPLAT OF

Explore the area: Key Biscayne homes for sale · Miami Dade County real estate

Bedrooms

Bathrooms

3,085

Living Sq Ft

1961

Year Built

Estimated monthly payment

$104,583 /mo

Principal and interest only, based on $3,980,000 down (20%), a 6.875% 30-year fixed rate. Property taxes, homeowners insurance are not included.

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Listing Snapshot

Price: $19,900,000
Days on Site: 15 Days
Bedrooms: 5
Total Baths: 4
Full Baths: 4
Partial Baths: 0
Living Area: 3,085 sqft
Total Sq Ft: 4,177 sqft
Lot Size: 0.51 Acres
Year Built: 1961
Property Type: Single Family
MLS #: A12071221
Property Tax: $201,741 (2026)
Subdivision: MASHTA ISLAND A REPLAT OF
County: Miami Dade
Status: Active
Special Conditions: Listed As Is

About This Property

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.

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General Features

Property Type: Single Family
Status: Active
Year Built: 1961
Property Condition: Resale
Number of Stories: 1
Levels: One
Garage Spaces: 2
Parking: Driveway
Direction Faces: East
Lot Size (Acres): 0.51
Living Sq Ft: 3,085
Total Sq Ft: 4,177
Sewer: Public Sewer
Water Source: Public
Zoning: 2001

Interior Features

Cooling: Central Air
Heating: Central
Flooring: Tile
Interior Features: Main Level Primary / Split Bedrooms
Total Rooms: 1

Exterior Features

Construction: Block
Roof: Barrel / Spanish Tile
Private Pool: Yes
Pool Features: In Ground
Waterfront: Yes
Waterfront Features: Bayfront / Ocean Access / Seawall
Frontage: Waterfront
Frontage Length: 138.00 ft
View: Bay / Ocean

Community & HOA

Association Amenities: Other
Financing Terms: Cash / Conventional
MLS Area: 2520

Schools

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

About the Area

Key Biscayne

View Key Biscayne Real Estate →

Browse Key Biscayne homes for sale across every neighborhood and price point in Miami-Dade. Available homes span single-family, townhome, and condo segments throughout the city. Key Biscayne includes gated golf communities, 55+ active adult neighborhoods, waterfront estates, and newer master-planned subdivisions. HOA fees vary by community type, from modest maintenance fees in non-gated subdivisions to higher dues in full-amenity country clubs. The city sits within Miami-Dade, offering access to South Florida beaches, major employment centers, and healthcare hubs. For current Miami-Dade market data, see Florida Realtors' monthly statistics. Browse the latest Key Biscayne listings below. Then connect with a Pure Equity Realty agent to schedule a private showing.

Homes for Sale: 169
Under Contract: 23
Median List Price: $2,560,000
Median Sale Price (July): $1,330,000
Median $/Sq Ft: $1,155
Avg Days on Market: 115

View all 169 homes for sale in Key Biscayne →

Frequently Asked Questions

How do I schedule a tour of 520 S Mashta Drive, Key Biscayne, FL 33149?: Use the Tour button on this listing to request a showing of 520 S Mashta Drive, Key Biscayne, FL 33149. Pick a day and time and choose an in-person or video-chat tour, and a Pure Equity Realty agent will confirm your visit, often the same day.
Is 520 S Mashta Drive, Key Biscayne, FL 33149 still available?: 520 S Mashta Drive, Key Biscayne, FL 33149 is currently listed as Active, and has been on the market 15 days. Status updates directly from the MLS as homes go under contract, so ask us to confirm availability before you plan a visit.
How much is the monthly payment for 520 S Mashta Drive, Key Biscayne, FL 33149?: With 20% down ($3,980,000) on the $19,900,000 list price and a 30-year fixed loan at an illustrative 6.875% rate, the estimated principal & interest for 520 S Mashta Drive, Key Biscayne, FL 33149 is about $104,583/mo, before property taxes, insurance. Use the payment estimate on this page to adjust the down payment and rate.
How do I get pre-approved to buy 520 S Mashta Drive, Key Biscayne, FL 33149?: Getting pre-approved shows sellers you're a serious buyer and clarifies your true budget before you offer on 520 S Mashta Drive, Key Biscayne, FL 33149. Contact Pure Equity Realty and we'll connect you with a trusted local lender to review your financing options, no obligation.
What schools serve 520 S Mashta Drive, Key Biscayne, FL 33149?: 520 S Mashta Drive, Key Biscayne, FL 33149 is zoned for Key Biscayne K-8 (elementary), Ponce De Leon (middle), Coral Gables (high). School assignments and boundaries can change year to year, so confirm current zoning with the local school district before you buy.
Can I negotiate the price of 520 S Mashta Drive, Key Biscayne, FL 33149?: Often, yes. The right offer on 520 S Mashta Drive, Key Biscayne, FL 33149 depends on how it's priced against comparable single family sales in Key Biscayne, how long it's been listed, and how motivated the seller is. Pure Equity Realty will run the comps and help you craft a competitive, well-supported offer.

Listing courtesy of Coldwell Banker Realty

Listing information is provided by BeachesMLS, Inc.and is deemed reliable but not guaranteed accurate by the MLS or Pure Equity Realty. Information is for consumers’ personal, non-commercial use and may not be used for any purpose other than to identify prospective properties. © 2026 BeachesMLS, Inc. Last updated August 30, 2026.

$19,900,000