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640 S Mashta Dr, Key Biscayne FL 33149
About this home
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
Features
- First Floor Entry
- Entrance Foyer
- Pantry
- Split Bedroom
- Vaulted Ceiling(s)
- Walk-In Closet(s)
- Garage Converted
- Other
- Bay
- Garden
Location
Approximate — shows the building, not the unit. Open in maps (opens in a new tab)
Estimated loan & HOA
Loan payment and HOA only. Property tax and insurance are significant here and are not included.
- Principal & interest
- $84,950
- HOA
- None
Illustration only — not a loan offer, quote, or commitment. Assumes a 30-year loan at 6.5% with 20% down (rates as of July 2026); your actual terms will differ.
Schedule a tour
Request a private or video tour with a local agent.
Run the numbers
We fill in the price and the building's HOA dues. That leaves rent, tax, insurance and maintenance — they depend on your exemptions, your insurer and the unit, so we don't guess them. Vacancy and the loan terms below start at common defaults; change them.
Enter rent, property tax, insurance, maintenance to see the returns. A cap rate calculated without every cost overstates the deal — often by half — so we don't show a partial one.
Illustration only — not a loan offer, quote, or investment advice. The loan fields start at 20% down over 30 years at 6.5% (rates as of July 2026); that is a nominal rate for illustration, not an APR, and your actual terms will differ. Cap rate is unlevered; cash-on-cash counts the down payment as invested capital and excludes closing costs.
Listing data from the MIAMI Association of REALTORS® (MIAMIRE) IDX program. Information deemed reliable but not guaranteed. Demo data shown for layout purposes.