ActiveMLS® A11990382

$16,800,000

640 S Mashta Drive, Key Biscayne, FL 33149

Beds: 4
Baths: 4
Sqft: 3,620

Est. payment$108,543/mo

Home type: Single Family Residence
Year built: 1968
Lot size: 14,810 sqft
Price / sqft: $4,641
HOA: $0/mo
Community: MASHTA ISLAND

Property description

Welcome to your own slice of paradise! Enjoy breathtaking sunsets from your private dock on this waterfront property boasting 100 feet of direct Biscayne Bay frontage. Ideally located on Mashta Island. Set on a 15,000 SF lot, the home features 5 beds, 5 baths, including 2 bayfront primary suites with stunning views, impact windows and doors throughout. The open-concept layout flows seamlessly from the living and dining areas to the modern kitchen and out to the pool and entertainment patio, with floor-to-ceiling glass doors that open to blend indoor and outdoor living. Tranquil guest suite upstairs offering privacy and views. It also features an oversized 2-car garage, covered parking, and a spacious driveway for guests. Perfect to move in, renovate, or build your dream waterfront estate

Listing activity

Days on market: 170
Listed: Apr 2, 2026
MLS listing updated: Sep 19, 2026
Feed last checked: 8 minutes ago

Listed by Brigitte De Langeron · DLS International Realty

Map

Map location is based on MLS-supplied coordinates. Verify the location before relying on it.

Facts & features

Interior

Bedrooms & bathrooms

Bedrooms: 4
Bathrooms: 4
Bathrooms (decimal): 4
Full bathrooms: 4
Half bathrooms: 0

Rooms & features

Rooms: 1
Interior features: Bedroom Layout - Split, Entrance Foyer, Pantry, Vaulted Ceiling(s), Walk-In Closet(s)
Flooring: Other
Appliances: Dishwasher

Heating & cooling

Heating: Other
Cooling: Central Air

Property

Parking

Garage spaces: 2
Garage: Yes
Covered spaces: 2
Parking features: Attached, Attached Garage, Driveway, Garage, Garage Door Opener, Guest
Attached garage: Yes

Exterior

Building area: 4,990 sqft
Entry level: 1
Exterior features: Other
Pool: Yes
Pool features: In Ground
View: Bay, Garden
Waterfront: Ocean
Waterfront property: Yes

Lot

Lot size: 14,810 sqft
Lot size (acres): 0.34 acres
Lot dimensions: 15000
Zoning: 2001
Road frontage: Public Road

Construction

Type & style

Home type: Single Family Residence
Architectural style: Other
Year built: 1968
New construction: No

Materials

Construction: Block
Roof: Barrel
Property condition: Resale
Faces: East

Utilities & green energy

Utilities

Sewer: Public Sewer
Water: Public
Utilities: Cable Available

Community & HOA

Community

Subdivision: MASHTA ISLAND
MLS area: 2520
Pets allowed: Dogs OK, Yes
55+ community: No

Association

Has association: No
Estimated monthly dues: $0

Lease details

Not reported by the listing source.

Location

Area details

City: Key Biscayne
County: Miami-Dade
ZIP code: 33149

Manufactured home details

Not reported by the listing source.

Financial & listing details

Listing

MLS number: A11990382
Possession: Close Of Escrow
Original list price: $16,800,000
Parcel number: 2452050080320
Annual property tax: $155,651
Tax year: 2025
Tax legal description: MASHTA ISLAND PB 60-93 LOT 9 BLK 3 LOT SIZE 100.000 X 150 OR 18642-3922 0599 1

Additional MLS details

Reported by the listing source

Association: No
Bathrooms Total Decimal: 4
Bathrooms Total Integer: 4
Building Area Total: 4990
Construction Materials: Block
County Or Parish: Miami-Dade
Days On Market: 170
Direction Faces: East
Elementary School: Key Biscayne K-8
High School: Coral Gables
List Price: 16800000
Listing Contract Date: 2026-04-02
Living Area: 3620
Lot Size Acres: 0.34
Lot Size Area: 15000
Lot Size Dimensions: 15000
MLSArea Major: 2520
Middle Or Junior School: Ponce De Leon
Mls Status: Active
On Market Date: 2026-04-02
Photos Count: 38
Postal Code: 33149
Property Sub Type: Single Family Residence
Property Type: Residential
Road Frontage Type: Public Road
Rooms Total: 1
Senior Community: No
Standard Status: Active
State Or Province: FL
Status Change Timestamp: 2026-04-02T04:00:00Z
Subdivision Name: MASHTA ISLAND
Water Source: Public
Waterfront Features: Ocean
Tax Annual Amount: 155651
Bathrooms Full: 4
Pool Private: Yes
Bedrooms Total: 4
Bathrooms Half: 0

Market value

Automated estimate—No licensed valuation source connected

Estimated sales range—Ask Karim for a local market analysis

Estimated rent—No licensed rental valuation source connected

Price history

Date	Event	Price
Apr 2, 2026	ListedMIAMI REALTORS® MLS	$16,800,000$4,641/sqft

Public tax history

Year	Property taxes	Assessment
2025	$155,651	—

Payment calculator

Estimated monthly payment$108,543/moIllustrative estimate, not a loan offer.

Loan typeDown payment (%)Interest rate assumption (%)Loan termInsurance / month

Principal & interest: $87,172
Property taxes: $12,971
Insurance: $8,400
Association dues: $0

Live national rate context is displayed below through Mortgage News Daily’s official widget. The calculator rate remains a separate assumption until licensed machine-readable access is connected. This is not a loan offer.

Neighborhood

Area

MASHTA ISLAND

Key Biscayne · Miami-Dade County · 33149

Climate risk

—

No licensed climate-risk source is connected.

Nearby schools

Key Biscayne K-8Elementary

—

Ponce De LeonMiddle

—

Coral GablesHigh

—

School names and districts are MLS-reported when available. Verify attendance boundaries with the school district. Ratings require a licensed ratings provider.

Nearby homes

12 homes

$18,500,0004 bd · 5 ba · 2,255 sqft631 N Mashta Drive, Key Biscayne, FL 33149