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    580 & 590 10th Street Key Colony Beach, FL 33051

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    For Sale
    $3,250,000

    Multi-family - Key Colony, FL

    Type:Multi Family
    Property size:
    4,478 SF
    Price / SF:
    $725/SF
    Added:
    Apr 24, 2026
    Days on Market:
    9
    Last Refresh:
    May 2 at 4:06 pm

    Property Features for 580 & 590 10th Street

    General Information

    Property type
    Residential Multi Family
    Property subtype
    Multi Family
    Zoning
    R-2A - Key Colony Two Family
    Bedrooms
    7
    Bathrooms
    7
    Rooms
    Bathroom 1, Bathroom 2, Bathroom 3, Bathroom 4, Bathroom 5, Bedroom 1, Bedroom 2, Bedroom 3, Bedroom 4, Bedroom 5
    Parking features
    Garage, Guest
    Spa
    1
    Interior features
    Drapes/Blinds Incl, Built-in Cabinets, Window Treatments, Smoke Alarms, Granite Counter Top, Entrance Foyer, Wet Bar
    Exterior features
    Fencing, Storage, Outdoor Shower, Lanai, Lighting, Hot Tub
    Fencing
    Fenced
    Appliances
    Dishwasher, Dryer, Microwave, Range, Refrigerator, Washer
    Standard status
    Active
    APN
    00075930-000000
    Size
    4,478 SF

    Taxes and HOA fees

    Tax Year
    2025
    Tax Annual Amount
    19308

    Utilities

    Cooling system
    Ceiling Fan(s)
    Water front features
    Canal Front, Waterfront
    Water front
    1

    Building Details

    Year built
    1985
    Floors in Building
    2
    Flooring type
    Carpet, Tile
    Roof type
    Metal
    Architectural style
    Other
    Additional Structures
    Storage

    We can help!

    Listing Contact
    Nate Bartlett
    Nate Bartlett

    Listing agent Nate Bartlett License #358818989

    Listing office Berkshire Hathaway HomeServices Keys Real Estate 9141 Overseas Highway, Marathon, FL

    Listing date Apr 24, 2026

    MLS# 617788 Listing URL

    Copyright © 2026 Marathon and Lower Keys Association of Realtors. All rights reserved. All information provided by the listing agent/broker is deemed reliable but is not guaranteed and should be independently verified.

    Overview

    Canal-Front Duplex with Rental Potential

    This expansive 7-bedroom, 7-bath residence in Key Colony, Florida, presents a canal-front opportunity with income potential. Functioning as a legal duplex with an interior lockout, the property can serve as a large single-family home or two separate living spaces. The configuration includes a 5-bedroom, 4-bath main residence and a 2-bedroom, 2-bath guest wing, with a pool bath located in the game room. This layout is suitable for multigenerational living, guests, or vacation rentals. The main living space features a two-story entry, an open-concept great room, multiple dining areas, a wet bar, and a kitchen that flows to a waterside balcony. The lower-level unit has its own open living and kitchen area. Four bedrooms are ensuite, with 2 primary suites overlooking the water. Mediterranean-inspired design elements are present throughout, along with impact windows and doors, and multiple balconies. Outdoor features include a heated pool, spa, covered poolside lanai, and 75 feet of concrete dockage with boating access to the Atlantic Ocean and the Gulf of America. Additional features include a two-car garage and ample off-street parking. Recent upgrades include complete concrete spalling repairs and a fresh exterior repaint. The property, with a size of 4478 square feet, has a vacation rental history and is currently an active rental.
    Property Profile Insight Report Location Intelligence

    Current Use by Public Records

    Duplexes

    Map

    City
    Key Colony Beach
    County
    Monroe
    State
    Florida
    Longitude
    -81.0216
    Latitude
    24.7226

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    FAQs

    What type of property is this?
    Duplex - 7-bedroom, 7-bath canal-front duplex with income potential.
    Where is this duplex located?
    The property is located at 580 & 590 10th Street Key Colony Beach, FL.
    What is the asking price?
    The asking price for this property is $3,250,000.
    What are key features of this property?
    This property features: Canal‑front property with **75 feet of concrete dockage** and quick boating access to the Atlantic Ocean and the Gulf of Mexico.; Legal duplex with interior lockout offers flexibility as a single‑family home or two separate living spaces (5BR/4BA main residence and 2BR/2BA guest wing).; Proven income potential with a strong, established vacation rental history and currently an active rental.
    (305) 800-6283
    We can help!
    Listing Contact
    Nate Bartlett
    Nate Bartlett
    Real Estate License ID: 358818989
    Learn More
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    Realmo Value Estimations

    Realmo estimates a property’s market value using a proprietary methodology that incorporates public data and user-submitted information. This cumulative value is generated by integrating a variety of conventional and innovative methods. 

    Disclaimer

    These figures are not official appraisals and should not be used as a substitute for a valuation performed by a licensed appraiser.
    Actual market value may differ due to factors not captured in the data. Estimates are offered for informational purposes only, and users should conduct independent research before making financial or investment decisions.
    By using this feature, you acknowledge that Realmo is not responsible for actions taken based on these estimates.

    AI approach

    Realmo AI Method estimates property value using machine learning models trained on millions of comparable listings, transactions, and market signals. It analyzes property features, location intelligence data, and current market dynamics to predict the most probable market value in real time.

    Realmo CapRate Calculation

    Realmo calculates the Capitalization Rate (Cap Rate) to help estimate a property's potential return on investment. The Cap Rate is a fundamental metric in commercial real estate that measures the relationship between a property's net operating income and its market value.

    How We Calculate Cap Rate

    Cap Rate Formula:
    Cap Rate (%) = (Net Operating Income / Property Value) × 100

    Net Operating Income (NOI) Formula:
    NOI = Area × Lease Rate × (1 - Vacancy Rate) × (1 - Operating Expense Ratio)

    Components

    Net Operating Income (NOI) represents the annual income a property generates after operating expenses:

    • Area: Building square footage from property records
    • Lease Rate: Annual $/sqft based on market data for the property type and geographic location
    • Vacancy Rate: Percentage of unoccupied space based on market data for the property type and location
    • Operating Expense Ratio: Operating costs as a percentage of income, varies by property type

    Property Value is derived from:

    • Recent sale price (if available)
    • Statistical models using comparable sales
    • AI-powered valuation estimates

    Example Calculation

    For a 100,000 sqft Office Building:

    • Lease Rate: $25.00/sqft/year (market data for Office in this area)
    • Vacancy Rate: 8% (market data for Office in this area)
    • Operating Expense Ratio: 35% (typical for Office properties)
    • Property Value: $15,000,000

    Step 1: Calculate NOI

    NOI = 100,000 × $25.00 × (1 - 0.08) × (1 - 0.35)
    NOI = 100,000 × $25.00 × 0.92 × 0.65
    NOI = $1,495,000/year

    Step 2: Calculate Cap Rate

    Cap Rate = ($1,495,000 / $15,000,000) × 100
    Cap Rate = 9.97%

    Property Type Considerations

    Net Operating Income calculations vary by property type due to different operating expense ratios:

    • Office: Higher expenses (30-40%) for HVAC, utilities, maintenance
    • Retail: Moderate expenses (25-35%) for common area maintenance
    • Industrial/Warehouse: Lower expenses (15-25%) for minimal tenant services
    • Multifamily: Moderate expenses (35-45%) including property management
    • Self-Storage: Lower expenses (25-35%) due to minimal maintenance

    Market lease rates and vacancy rates are specific to each property type and geographic location, reflecting local market conditions.

    Disclaimer

    These calculations are estimates for informational purposes only and should not be used as a substitute for professional financial analysis or appraisal.

    • Cap Rate calculations depend on market data that may change over time
    • Actual operating expenses, lease rates, and vacancy rates may differ from market averages
    • Individual property conditions, lease terms, and tenant quality significantly impact actual NOI
    • Property value estimates are approximations and not official appraisals
    • Cap rates vary widely by market, property condition, and investment risk profile

    Professional Guidance Recommended: Before making any investment or financial decisions, consult with licensed appraisers, commercial real estate brokers, and financial advisors who can evaluate your specific property and circumstances.
    By using this feature, you acknowledge that Realmo is not responsible for investment decisions or actions taken based on these estimates.

    Cap approach

    Capitalization Method calculates value based on estimated net operating income (NOI) and applying a market-based capitalization rate (cap rate), we estimate what a typical investor might be willing to pay for it.

    Comparable approach

    Comparable estimate is based on recent sales of similar nearby properties, adjusted for factors like size, condition, and location.

    Relative

    Relative property class coefficient uses factors that account for typical price differences between various asset types (e.g., retail vs. industrial) to provide a more accurate market-aligned estimate.

    Geo

    Comparable Sales Method, enhanced by Geo coefficients — location-based adjustment factors that reflect differences in price levels across neighborhoods, cities, or regions ensuring a more accurate, market-sensitive valuation.

    Stat Estimate

    This method estimates value based on actual market adjusted recent (~5 years) sales of comparable properties around by location and property type.

    • Ranges - area data calculated by industry standard IQR Outlier Removal Method
    • Range-from: 75% of all similar sales ($/sqft) are above this value
    • Range-to: 75% of all similar sales ($/sqft) are below this value
    AI Estimate

    This method estimates value based on AI market estimation of comparable properties around by location and property type.

    • Ranges - area data calculated by industry standard IQR Outlier Removal Method
    • Range-from: 75% of all estimations ($/sqft) are above this value
    • Range-to: 75% of all estimations ($/sqft) are below this value
    Alternative use

    Estimate considers the property’s potential value if used for a different purpose-based on zoning, demand, and market feasibility.

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    580 & 590 10th Street, Key Colony, FL 33051

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