KEY HARBOR
Homes for Sale in Marathon, FL
True comps, carrying-cost math, and listings before the portals.
Market Heat
Key Harbor sits in Marathon, Monroe County — the Florida Keys — and that geography is the primary price driver. Waterfront and water-access land in the Keys is constitutionally finite, and that scarcity has pushed the median here to $350,000 while sustaining a year-over-year gain of 7.7 percent. The long-arc number is harder to ignore: values have risen roughly 320 percent since 2012, a pace that reflects both the broader Keys premium and the near-impossibility of meaningful new supply entering this market.
What catches attention right now is the median days-on-market sitting at less than one day — effectively, properties are going under contract the same day they list. A market-heat score of 72 confirms this is a seller's environment. Buyers need to arrive pre-approved, with a clear price ceiling, and ready to move without the luxury of a weekend to think it over. Sellers, in turn, should resist the temptation to overprice; the velocity here rewards accurate list prices, not aspirational ones.
KEY HARBOR right now
🟡 Still climbing. The trailing-12-month median ($350K) is up 7.7% from the prior 12 months ($325K) and up 320% since 2012. With about 2 sales a year, a single closing can swing this number, so read the level and the decade, not one year's move.Momentum Research, record-level floridakeys closed sales, 12-month windows ending July 27. Confidence: Low (6 and 4 sales in the two windows).
What's unique here: the median sale price is about 63% below the typical Monroe County sale ($350K vs $950K, trailing 12 months, floridakeys records).
Jump to: Price history & scorecard · Homes for sale · Schools · FAQ
Updated July 27, 2026 · Live data: floridakeys, refreshed twice daily · MLS facts carry their source; interpretation lines are Momentum Research · Data sources & freshness
The 60-Second Overview
KEY HARBOR market snapshot (as of July 27, 2026): the median sale price is about $350K, and a median 1 days on market for closed sales. The trailing-12-month median is up 8% from the prior 12 months and up 320% since 2012, computed from record-level floridakeys closed sales (6 closings in the current window).
Key Harbor is a Marathon community operating inside one of Florida's most supply-constrained corridors, where the combination of island geography and limited buildable land keeps demand structurally elevated and inventory consistently thin.
Who KEY HARBOR is best for.
Best for
- A buyer with a firm pre-approval at or above the $350,000 median who can submit an offer the day a listing goes live.
- An investor or second-home buyer focused on long-term hold in a geographically constrained market, comfortable with the insurance and maintenance realities of a coastal Keys property.
- A seller-side client who owns here and has been waiting for a strong exit: sub-one-day absorption and 7.7 percent year-over-year gains represent a well-timed listing window.
Probably not for
- A buyer who needs several days to tour, consult, and deliberate before committing — this market's pace will not accommodate that process.
- A buyer whose budget requires a price-range ceiling well below the current median, or who is counting on negotiating down from list price in a near-zero-DOM environment.
- A buyer prioritizing a community with organized amenities such as a pool, fitness center, or HOA-managed common areas — none are currently identified in this community's MLS data.
Price History: What Homes Here Have Actually Sold For
Median sale price over the trailing 12 months ending July 27 of each year, from record-level floridakeys closed sales. Same methodology as every appreciation figure on this page: the 2026 point ($350K) IS the median in the snapshot above, and the move from 2025 ($325K) IS the +7.7% one-year change.
Windows contain 0 to 14 sales each (6 in the current window); every figure carries its sample size, and thin markets swing on single closings. Listing data provided by Florida Keys MLS, Inc. Information is deemed reliable but is not guaranteed by the MLS to be accurate. Deemed reliable but not guaranteed.
The real cost & risk here
Before the list price, the Florida math the portals skip. These are Monroe County typicals — your exact home, flood zone, and insurance quote will vary, so verify each before you offer.
Check it for your address: look up your flood zone (FEMA) · insurance by county · true-cost calculator · Monroe County scorecard.
County typicals from Momentum’s Florida housing data (Zillow & Realtor.com aggregates, Census, FRED), updated monthly; insurance modeled. Flood zone is property-specific — always confirm via FEMA.
The KEY HARBOR buying strategy.
If we were buying in KEY HARBOR today, this is the order of operations we would run for our clients.
Underwrite the condition first. Price the roof, HVAC, and systems honestly before judging any list price; condition swings value here more than square footage alone.
Match the home to real comps. Recent sales of similar condition and lot, not the asking price, tell you what a home is worth.
Move deliberately, not desperately. Neither side has a decisive edge, so a well-prepared, fairly-priced offer wins without overpaying.
Line up financing and inspection early. A pre-approval and an inspection plan let you act fast and negotiate from evidence.
Keep an agent in your corner. The listing agent works for the seller; we represent you and prepare a hand-built valuation before any offer in KEY HARBOR.
Reading the Keys Market Correctly
A median price of $350,000 in the Florida Keys buys something meaningfully different than the same figure on the mainland. Monroe County's strict land-use controls, FEMA flood regulations, and the physical limits of the island chain mean that comparable replacement inventory simply does not materialize the way it does in most Florida markets. Buyers should understand they are not just purchasing a property — they are buying into a constrained system where the rules of supply and demand operate with unusual force.
MLS data for the current six-month window shows no community amenities identified from active listings, which means buyers should not factor a managed amenity package into their underwriting. That is not necessarily a negative — Keys buyers often prioritize the natural environment and water access over clubhouses or fitness centers — but it is a concrete fact worth setting expectations around. Price variation within Key Harbor is likely condition- and access-driven; a similar footprint can carry a meaningfully different value depending on lot type, elevation, and the condition of existing structures in a coastal environment that is hard on buildings.
The location and the amenities are priced into every listing in KEY HARBOR. The deal is won or lost on condition, the comps, and the renovation math.
Momentum Buy Score.
Our proprietary 0 to 10 read across the factors that decide how a home in KEY HARBOR buys, holds, and resells. Momentum Research; not an appraisal.
Momentum Intelligence Scores are our proprietary, qualitative assessment on a 0 to 10 scale, built from the record-level market data on this page. They are a framework for comparing communities, not a guarantee of future value and not advice on a specific home; unlike an automated value estimate they do not price your home, they grade the community on evidence you can inspect. Composite is the plain average of the 3 factors (9.3). Basis: Long-Term Appreciation +320% since 2012; Recent Direction +7.7% year-over-year; Pricing Power 100.0% sale-to-list. Refreshed with each data update.
Why work with Momentum here
Monroe County transactions carry layers that mainland deals do not: flood zone classifications, elevation certificates, wind mitigation, the interplay of FEMA regulations and local building codes, and title issues that can be uniquely complex in the Keys. Momentum Realty works the Northeast Florida and Keys feed with brokers who know which questions to ask before an offer is written, not after inspection. In a market where the median days-on-market is measured in hours, having an agent who can read a listing, structure clean terms, and move without hesitation is not a luxury — it is the only realistic path to a closed deal.
KEY HARBOR in 15 seconds.
HOA, CDD & Fees
- Mandatory HOA — confirm current dues
- Any club/amenity membership is billed separately
Confirm the current HOA dues, exactly what they cover, and any CDD bond or special assessment for a specific address before you offer.
Tools for a KEY HARBOR buy.
Free calculators to pressure-test the real cost before you tour.
Selling here is won on condition and pricing to real comps, not an automated estimate. The right number comes from closed KEY HARBOR sales matched to your home.
Price it to the comps and condition, not an automated estimate.
If you are thinking about selling in KEY HARBOR, the right list price comes from recent comparable sales matched to your home's condition and location, not an automated estimate.
What is your KEY HARBOR home worth?
Get a no-obligation home value based on real comparable sales in KEY HARBOR, not an automated guess. Tell us about your home and we will personally prepare your numbers and a pricing strategy. No obligation, no spam.
See homes for sale in KEY HARBOR on the map →
Frequently Asked Questions
What is the median home price in KEY HARBOR?
How long do homes in KEY HARBOR take to sell?
Do cash buyers compete in KEY HARBOR?
Have KEY HARBOR home prices gone up?
Who is the best real estate agent for KEY HARBOR?
How do I find a top Marathon real estate agent who knows KEY HARBOR?
Can Momentum Realty connect me with an agent for KEY HARBOR?
Should you buy in KEY HARBOR?
An honest fit check. We will tell you when it is not your community.
Data sources & freshness
| Community market stats | floridakeys closed sales, 12-month windows ending July 27, 2026 |
| Historical depth | Closed-sale records back to 2003 (89 transactions analyzed) |
Verify the primary sources yourself: Florida DOR · U.S. Census · FEMA flood maps · Citizens Property Insurance.
Momentum Research figures are our own analysis of floridakeys records; MLS data is deemed reliable but not guaranteed. Methodology: how Momentum market scores are computed. Market metrics describe homes for sale and recent sales, not residents.
Own a home here?
You just read the data. Now see what your home is worth.
The numbers on this page move markets in the aggregate. The number that matters to you is what a buyer pays for your address. Momentum sells for 1.25% above the floridakeys member average and 8 days faster, and we’ll price yours against live your area comps.
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More Marathon & The Florida Keys & Monroe County guides
Compare before you commit - every guide covers pricing, HOA/CDD, insurance posture, and fit. Browse all of The Florida Keys & Monroe County or the full Neighborhood Finder.