How much is 631 N Mashta Drive?

631 N Mashta Drive is listed at $18,500,000, which is about $8,204 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 631 N Mashta Drive?

The listing reports annual property taxes of $112,485 for 2025. 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 631 N Mashta Drive built?

631 N Mashta Drive was built in 1958 and the listing describes its condition as resale updated/remodeled. 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 631 N Mashta Drive been on the market?

631 N Mashta Drive has been listed for 102 days. Days on market and price changes are the first signals of how much room there is to negotiate.

Is 631 N Mashta Drive waterfront?

Yes. The listing describes the water as no fixed bridge ocean access navigable water seawall bayfront intracoastal. 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 631 N 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 631 N 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.

631 N Mashta Drive, Key Biscayne, FL 33149

$18,500,000 · Active

4 beds
4.5 baths
2,255 sq ft
102 days on market
Single Family Residence
Built 1958
Updated/Remodeled
Lot 14,810.4 sq ft
3,720 sq ft total
Miami-Dade County
MLS# B26058354
Mashta Island

Aerial at 631 N Mashta Drive, Key Biscayne

house at 631 N Mashta Drive, Key Biscayne

driveway at 631 N Mashta Drive, Key Biscayne

Back of the house at 631 N Mashta Drive, Key Biscayne

About this home

BRING ALL OFFERS! Exceptional waterfront opportunity in prestigious Key Biscayne. Set on a 15,000 sq. ft. lot with 100 feet of water frontage, this residence offers open-water views, direct Biscayne Bay access, and no fixed bridges to the ocean. Currently undergoing a complete renovation, it will feature modern finishes, impact windows and doors, new systems, spacious living areas, a chef's kitchen, and luxurious bathrooms. Enjoy a private dock, deep-water access, pool, breathtaking sunsets, and an unmatched boating lifestyle in one of South Florida's most desirable communities One of the most compelling waterfront opportunities currently available in all of Key Biscayne. Perfectly positioned on the exclusive and highly coveted Mashta Island, this exceptional property offers approximately 100 feet of prime waterfront, deep-water dockage, direct Biscayne Bay access, and no fixed bridges to the Atlantic Ocean, creating an unparalleled opportunity for boating enthusiasts and yacht owners. Mashta Island has long been recognized as one of South Florida's most prestigious residential enclaves, offering exceptional privacy, quiet tree-lined streets, oversized waterfront estates, and immediate access to the open waters of Biscayne Bay while remaining only minutes from Brickell, Downtown Miami, Coconut Grove, Coral Gables, Miami Beach, and Miami International Airport. Very few neighborhoods offer this combination of island living, security, boating lifestyle, and proximity to the city's financial and cultural centers. The residence is currently on renovation designed to transform the property into a contemporary waterfront estate while preserving the exceptional value of its location and oversized waterfront parcel. This is substantially more than a cosmetic renovation. The project includes major improvements throughout the residence, including redesigned living spaces, upgraded electrical and plumbing systems, new HVAC equipment, impact-resistant windows and doors, premium flooring, modern architectural lighting, designer finishes, and a completely reimagined interior intended to meet today's luxury lifestyle expectations. Upon completion, the home is anticipated to offer spacious entertaining areas, beautifully appointed bedroom suites, bathrooms, an impressive chef's kitchen featuring custom cabinetry, premium appliances, elegant countertops, and thoughtfully designed indoor-outdoor living spaces that maximize the spectacular waterfront setting. The property's exceptional orientation provides beautiful water views and unforgettable sunsets while creating an ideal environment for entertaining, family gatherings, and year-round outdoor living. The expansive backyard offers generous space surrounding the swimming pool together with multiple areas for outdoor dining, lounging, and enjoying the waterfront lifestyle that has made Key Biscayne one of the most desirable residential communities in South Florida. For boating enthusiasts, few properties can offer the combination of oversized waterfront, private dockage, deep-water access, and unrestricted navigation to Biscayne Bay and the Atlantic Ocean without fixed bridges. Whether accommodating a large sport yacht, cruising yacht, center console, or multiple vessels, the waterfront configuration provides flexibility rarely available in today's market. Key Biscayne continues to be recognized as one of South Florida's most exclusive island communities, celebrated for its pristine beaches, excellent schools, private clubs, marinas, tennis facilities, parks, bicycle paths, restaurants, and relaxed coastal lifestyle. Residents enjoy the unique advantage of living within a peaceful island environment while remaining only a short drive from Miami's world-class shopping, fine dining, cultural institutions, private airports, international business centers, and professional sports venues. The supply of premium waterfront homes on Mashta Island remains extremely limited due to the neighborhood's established character and finite number of waterfront parcels. As a result, opportunities to acquire large waterfront lots with substantial dockage and direct ocean access continue to be highly sought after by both domestic and international buyers. The combination of location, waterfront dimensions, boating accessibility, oversized lot, and comprehensive renovation creates a property with exceptional long-term appeal. Showings are strictly by appointment with the Listing Agent.. All measurements, dimensions, lot size, square footage, waterfront frontage, dock dimensions, room sizes, zoning, taxes, permits, specifications, plans, renderings, and property information are believed to be accurate but are not guaranteed and should be independently verified by Buyer. Renderings, conceptual plans, floor plans, specifications, and construction updates are available upon request when applicable. This offering represents an extraordinary opportunity to secure one of Key Biscayne's waterfront residences . Whether as a primary residence, seasonal retreat, or long-term investment, this property combines one of South Florida's most desirable locations with an outstanding boating lifestyle and exceptional future value. Bring All Offers.

Features

Entrance Foyer
Walk-In Closet(s)
Garden
Private Rooftop Terrace
No Fixed Bridge
Ocean Access
Navigable Water
Seawall
Bayfront
Intracoastal
In Ground
Equipment Included

Schools

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

Presented by

BreakThru Realty · (786) 914-1017

Courtesy of

Coldwell Banker · joseph.santini@floridamoves.com · Listing agent: Javier Gustavo Quiroz

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 631 N Mashta Drive.

Before You Make an Offer

Buying a waterfront home: ocean access, bridges and docks

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 631 N Mashta Drive

How much is 631 N Mashta Drive?: 631 N Mashta Drive is listed at $18,500,000, which is about $8,204 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 631 N Mashta Drive?: The listing reports annual property taxes of $112,485 for 2025. 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 631 N Mashta Drive built?: 631 N Mashta Drive was built in 1958 and the listing describes its condition as resale updated/remodeled. 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 631 N Mashta Drive been on the market?: 631 N Mashta Drive has been listed for 102 days. Days on market and price changes are the first signals of how much room there is to negotiate.
Is 631 N Mashta Drive waterfront?: Yes. The listing describes the water as no fixed bridge ocean access navigable water seawall bayfront intracoastal. 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 631 N 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 631 N 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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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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The 4 bedroom home at 640 S Mashta Drive, Key Biscayne, FL 33149 is comparable and listed for sale at $16,800,000. Another comparable home, 591 N Mashta Drive, Key Biscayne, FL 33149, sold for $14,000,000 in August 2026. Other 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.