$18,500,000
631 N Mashta Drive
Key Biscayne, FL 33149
Explore the area: Key Biscayne homes for sale · Miami Dade County real estate
Price Check
How this price compares
- List price
- $18,500,000
- Price per sq ft
- $8,204
- Original price
- Unchanged
- Days on market
- 63
This 4-bedroom single-family home in Mashta Island is listed at $18,500,000, or $8,204 per square foot. It has been on the market for 63 days.
Estimated monthly payment
$97,225 /mo
Principal and interest only, based on $3,700,000 down (20%), a 6.875% 30-year fixed rate. Property taxes, homeowners insurance are not included.
Customize this estimateListing Snapshot
- Price
- $18,500,000
- Days on Site
- 63 Days
- Bedrooms
- 4
- Total Baths
- 5
- Full Baths
- 4
- Partial Baths
- 1
- Living Area
- 2,255 sqft
- Total Sq Ft
- 3,720 sqft
- Lot Size
- 0.34 Acres
- Year Built
- 1958
- Property Type
- Single Family
- MLS #
- B26058354
- Property Tax
- $112,485 (2025)
- Subdivision
- MASHTA ISLAND
- County
- Miami Dade
- Status
- Active
- Special Conditions
- Standard
About This Property
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.
Virtual TourGeneral Features
- Property Type
- Single Family
- Status
- Active
- Year Built
- 1958
- Property Condition
- Resale / Updated Remodeled
- Number of Stories
- 1
- Levels
- One
- Parking
- Attached Carport / Circular Driveway / Carport / Driveway
- Direction Faces
- East
- Lot Size (Acres)
- 0.34
- Living Sq Ft
- 2,255
- Total Sq Ft
- 3,720
- Structure Type
- House
- Sewer
- Public Sewer
- Water Source
- Public
- Zoning
- 2001
Interior Features
- Appliances
- Cooktop / Dryer / Dishwasher / Energy Star Qualified Dishwasher / Energy Star Qualified Dryer / Energy Star Qualified Freezer / Energy Star Qualified Refrigerator / Energy Star Qualified Washer / Electric Cooktop / Electric Water Heater / Free Standing Freezer / Microwave / Oven / Refrigerator / Water Heater / Wine Refrigerator / Washer
- Cooling
- Central Air
- Heating
- Central / Electric
- Flooring
- Concrete / Laminate / Tile
- Interior Features
- Dual Sinks / Entrance Foyer / Living Dining Room / Walk In Closets
- Laundry
- Inside / Laundry Room / Laundry Tub / Sink
- Windows
- Storm Windows
- Main Level Bedrooms
- 4
- Main Level Baths
- 4
- Furnished
- Unfurnished
Exterior Features
- Construction
- Brick / Concrete
- Roof
- Shingle
- Exterior Features
- Garden / Outdoor Living Area
- Private Pool
- Yes
- Pool Features
- In Ground / Pool Equipment
- Patio & Porch
- Covered / Patio / Rooftop
- Lot Features
- Quarter To Half Acre Lot / Sprinklers Automatic / Sprinkler System
- Waterfront
- Yes
- Waterfront Features
- Bayfront / Intracoastal Access / Navigable Water / No Fixed Bridges / Ocean Access / Seawall
- Frontage
- Waterfront
- Frontage Length
- 100.00 ft
- View
- Bay / Intercoastal / Pool / Water
Community & HOA
- Utilities
- Electricity Connected / Sewer Connected / Water Connected
- Pets Allowed
- No Pet Restrictions / Yes
- Financing Terms
- Cash / Conventional
- Restrictions
- See Remarks
- MLS Area
- 2520
Schools
- Elementary School
- Key Biscayne K-8
- Middle School
- Ponce De Leon
- High School
- Coral Gables
About the Community
- Homes for Sale
- 2
- Median List Price
- $17,650,000
- Median $/Sq Ft
- $6,422
- Avg Days on Market
- 119
Frequently Asked Questions
- How do I schedule a tour of 631 N Mashta Drive, Key Biscayne, FL 33149?
- Use the Tour button on this listing to request a showing of 631 N Mashta Drive, Key Biscayne, FL 33149. Pick a day and time and choose an in-person or video-chat tour, and a Pure Equity agent will confirm your visit, often the same day.
- Is 631 N Mashta Drive, Key Biscayne, FL 33149 still available?
- 631 N Mashta Drive, Key Biscayne, FL 33149 is currently listed as Active, and has been on the market 63 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 631 N Mashta Drive, Key Biscayne, FL 33149?
- With 20% down ($3,700,000) on the $18,500,000 list price and a 30-year fixed loan at an illustrative 6.875% rate, the estimated principal & interest for 631 N Mashta Drive, Key Biscayne, FL 33149 is about $97,225/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 631 N 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 631 N Mashta Drive, Key Biscayne, FL 33149. Contact Pure Equity and we'll connect you with a trusted local lender to review your financing options, no obligation.
- What schools serve 631 N Mashta Drive, Key Biscayne, FL 33149?
- 631 N 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 631 N Mashta Drive, Key Biscayne, FL 33149?
- Often, yes. The right offer on 631 N 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 will run the comps and help you craft a competitive, well-supported offer.
Listing courtesy of Coldwell Banker
Listing information is provided by BeachesMLS, Inc.and is deemed reliable but not guaranteed accurate by the MLS or Pure Equity. 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 1, 2026.
$18,500,000
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Listed by Javier Gustavo Quiroz, Coldwell Banker
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Recent Sales
Recently sold homes in Mashta Island
These are the last 2 recorded closings in Mashta Island, with the price each home actually sold for rather than what it was listed at. They closed at a median of $1,538 per square foot. The most recent closed on August 11, 2026. Closed sales are what an appraiser and a buyer's agent will look at, so they are the starting point for pricing a home here.
Sold$5,200,000
Sold · August 11, 2026
669 S Mashta Drive
4 bed · 3.5 bath · 3,382 sqft · $1,538/sqft
$599,000 under the asking price
Sold$4,750,000
Sold · February 4, 2026
669 S Mashta Drive
3 bed · 3.5 bath · 3,382 sqft · $1,404/sqft
$200,000 under the asking price
See every recorded sale in Mashta Island or find out what your Mashta Island home is worth.
