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631 N Mashta Drive, 
Key Biscayne, FL 33149

$18,500,000


4

Beds


5

Baths


2,255

Sq Ft


Single Family


Virtual Tour

Active

Listed by

Javier Quiroz

Last updated:

August 11, 2026, 10:44 PM

MLS#

B26058354

Source:

RMLS

Company Logo

About This Home

631 N Mashta Drive

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.

Home Facts

Single Family

5 Baths

4 Bedrooms

Built in 1958

Subdivision & Development:

MASHTA ISLAND

Price Summary

18,500,000

$8,203 per Sq. Ft.

MLS #:

B26058354

Last Updated:

August 11, 2026, 10:44 PM

Added:

14 day(s) ago


Rooms & Interior

Bedrooms

Total Bedrooms:

4

Bathrooms

Total Bathrooms:

5

Full Bathrooms:

4

Interior

Living Area:

2,255 Sq. Ft.


Structure

Structure

Building Area:

3,720 Sq. Ft.

Year Built:

1958


Finances & Disclosures

Finances

Price:

$18,500,000

Price per Sq. Ft:

$8,203 per Sq. Ft.

631 N Mashta Drive
Source:RMLS
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 Beaches Multiple Listing Service, Inc. 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.

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Contact an Agent

Yes, I would like more information. Please use and/or share my information with a Coldwell Banker ® affiliated agent to contact me about my real estate needs. By clicking Contact, I request to be contacted by phone or text message and consent to being contacted by automated means. I understand that my consent to receive calls or texts is not a condition of purchasing any property, goods, or services. Alternatively, I understand that I can access real estate services by email or I can contact the agent myself.

If a Coldwell Banker affiliated agent is not available in the area where I need assistance, I agree to be contacted by a real estate agent affiliated with another brand owned or licensed by Anywhere Real Estate (BHGRE®, CENTURY 21®, Corcoran®, ERA®, or Sotheby's International Realty®). I acknowledge that I have read and agree to the terms of use and privacy notice.