Episode 2 · Property Types & Supply Dynamics
Key Biscayne Housing Stock: Condos, Houses, Holding Cost
Most Key Biscayne homes are condo units, but the island holds two very different kinds of home. This page sets condo units beside houses on their own land, showing how big and how old each one runs, how much of a house's value sits in the ground, who holds them, and why the tax cap on a long-held home does not pass to a buyer.
💡 Key Insights & Takeaways
- Of the 7,101 residential parcels on September 23, 2026, 5,621, or 79.2%, are condo units and 1,281, or 18.0%, are houses.
- The median house has 3,457 square feet of living space, more than double the 1,546-square-foot median condo unit.
- Houses fall into two age groups, with 36.0% built in the 1950s and 34.0% in 2000 or later, while the median condo unit was built in 1978.
- Land is 81.8% of the median house's just value, on a median land area of 7,838 square feet, so on a house you are mostly paying for the ground.
- A qualifying sale resets the cap, so a buyer does not inherit the gap below just value, a median $1,269,393 on a house with the exemption and $350,926 on a condo unit with it.
A sale changes what a Key Biscayne house is taxed on more than the house itself does. On September 23, 2026, the median house with a homestead exemption was assessed $1,118,445 below the median house without one, on similar just values. Houses are also the minority here, because 79.2% of the residential parcels are condo units.
At a glance
Key Biscayne in five numbers as of September 23, 2026, each worked on the 7,101-parcel residential universe or on the house and condo cohorts inside it.
| Measure | Value | Basis | As of |
|---|---|---|---|
| Residential parcels | 7,101 | Residential universe | 2026-09-23 |
| Condo units | 5,621 (79.2%) | Residential universe | 2026-09-23 |
| Houses | 1,281 (18.0%) | Residential universe | 2026-09-23 |
| Land's share of the median house's just value | 81.8% | 1,277 houses with a land and building split | 2026-09-23 |
| Carrying a homestead exemption | Houses 65.7% · condo units 33.7% | 1,281 houses · 5,621 condo units | 2026-09-23 |
What kind of homes are on Key Biscayne?
Most Key Biscayne homes are condo units. Of the 7,101 residential parcels on September 23, 2026, 5,621, or 79.2%, are condominium units, and another 130 are co-op units, so 81.0% of the village is held in one of those two forms. 1,281 parcels, or 18.0%, are houses. The rest is 63 parcels of vacant residential land and 6 multi-family buildings. The count covers homes only, and shops, offices, public land and shared common areas sit outside every figure on this page.
The condo count describes a legal form, not the shape of a building. Miami-Dade files the village's townhouses inside the same class, so a townhouse with its own front door and a unit on a high floor are counted alike, and no separate townhouse count exists.
Condo and co-op units also carry one combined value from the county, with no separate figure for the land and the building and no land area of their own. That is how Miami-Dade values this kind of home. It is why the land figures further down describe houses only, while size, age, value, ownership and tenure are shown for both.
What Key Biscayne is built of, across the 7,101-parcel residential universe, as of September 23, 2026.
| Property type | Parcels | Share of residential parcels |
|---|---|---|
| Condo units | 5,621 | 79.2% |
| Houses | 1,281 | 18.0% |
| Co-op units | 130 | 1.8% |
| Vacant residential land | 63 | 0.9% |
| Multi-family buildings | 6 | 0.1% |
How big and how old are Key Biscayne homes?
The median Key Biscayne house has 3,457 square feet of living space, more than double the 1,546-square-foot median condo unit, as of September 23, 2026. 30.9% of houses reach 4,000 square feet or more. Co-op units are smaller again, at a median of 1,320 square feet across 129 units.
Houses here tend to go up rather than out. 55.6% of them stand two stories or taller and 44.4% sit on one floor, across the 1,278 houses with a story count. The median house has 4 bathrooms, 73.1% have three or more, and only 6.9% make do with one. No single plan leads, and the most common, 4 bed / 3 bath, covers just 11.9% of houses. Condo units run the other way, with one plan, 2 bed / 2 bath, covering 56.2% of them.
The houses are two groups of very different ages. 36.0% went up in the 1950s and 34.0% in 2000 or later, and 0.0% are older than 1950. The median build year of 1985 therefore lands in the thin gap between them and describes few real houses. Check the build decade before you compare two houses, because a 1950s original and a new build are different purchases.
The condo stock is older and more even. The median condo unit was built in 1978, and 58.1% of units date from before 1980.
Size, age and layout of Key Biscayne homes, as of September 23, 2026. Houses are the 1,281-parcel house cohort and condo units the 5,621-unit condo cohort. A dash means the measure is not shown for that form.
| Measure | Houses | Condo units |
|---|---|---|
| Median living area | 3,457 square feet | 1,546 square feet |
| 4,000 square feet or more | 30.9% | — |
| Median land area, every house measured | 7,838 square feet | — one combined value, no land area |
| Median year built | 1985 | 1978 |
| Built in the 1950s | 36.0% | — |
| Built in 2000 or later | 34.0% | — |
| Built before 1980 | — | 58.1% |
| Two stories or more | 55.6% (n = 1,278) | — |
| Median bathrooms | 4 (n = 1,280) | — |
| Three or more bathrooms | 73.1% (n = 1,280) | — |
| Most common plan | 4 bed / 3 bath, 11.9% | 2 bed / 2 bath, 56.2% |
What does it cost to hold a Key Biscayne home?
The figure an owner pays tax on here turns on how long they have held, more than on the home. On September 23, 2026, the median house with a homestead exemption was assessed at $1,901,903 and the median house without one at $3,020,348. Their median just values sit much closer, at $3,043,055 and $3,265,738. Just value is the county's own valuation before exemptions and the cap. Assessed value is the capped figure a tax bill is worked from, and neither one is a sale price.
The cap is Florida's Save Our Homes rule. It holds the yearly rise in the assessed value of a homesteaded home to 3% or the change in the consumer price index, whichever is lower, while a looser yearly limit applies to homes without the exemption. So the longer an owner holds, the further the taxed figure falls behind the just value. The median homesteaded house sits $1,269,393 below its own just value, across 842 houses, and the median homesteaded condo unit sits $350,926 below its just value, across 1,897 units. Across all 5,621 condo units the median assessed value is $850,057 against a median just value of $1,007,460.
The cap does not travel with the deed. A qualifying sale resets the assessed value to the just value, so a buyer is taxed on the county's full valuation rather than on the seller's capped figure. Budget from the just value, never from the seller's current bill. Portability may let an eligible Florida owner carry part of their own saved gap to another Florida homestead, subject to the rules and to filing.
The same pattern shows against what owners paid. A qualified sale is one the county marks as a true market sale between unrelated parties. Across the 850 houses with a qualified sale of $10,000 or more behind them, the median assessed value stands at 1.03× the last sale price. Houses last sold in the 1980s are assessed at 3.62× that price (n = 36), and houses sold in the 2020s at 0.88× (n = 336). The 11 houses last sold in the 1970s sit at 8.14×, a directional figure at that count.
What the homestead exemption does to the assessed value of a Key Biscayne home, as of September 23, 2026. Every figure is a median.
| Measure | Value | n |
|---|---|---|
| House with the exemption, assessed value | $1,901,903 | 842 |
| House without it, assessed value | $3,020,348 | 439 |
| House with the exemption, just value | $3,043,055 | 842 |
| House without it, just value | $3,265,738 | 439 |
| Homesteaded house, gap between just value and assessed value | $1,269,393 | 842 |
| Homesteaded condo unit, gap between just value and assessed value | $350,926 | 1,897 |
| All condo units, assessed value | $850,057 | 5,621 |
| All condo units, just value | $1,007,460 | 5,621 |
| Houses, assessed value against the last qualified sale price | 1.03× | 850 |
Who owns Key Biscayne homes, and for how long?
Houses and condo units are two different ownership markets on Key Biscayne. 65.7% of houses carry a homestead exemption against 33.7% of condo units, as of September 23, 2026. The exemption goes to an owner whose permanent home the property is, so it is the closest thing to an occupancy count the assessment data gives, and a home without it is not proven to be empty or rented.
37.2% of houses are held in the name of an entity rather than a person, 15.5% in a trust and 21.7% in corporate or LLC form. On condo units the entity share is 50.5% and the corporate or LLC share is 37.0%. Trusts are an estate-planning tool common among owners who have held a long time, and they are not read here as investors. The corporate or LLC share is the closest figure to investor ownership, but an LLC is also a common privacy and liability wrapper for an owner who lives in the home, so it is not an investor count either.
Mailing addresses point mostly to Florida. 2.7% of house owners and 6.8% of condo owners mail to another US state, and 0.7% of all residential owners mail from outside the US. An owner who mails to the home, to a local agent or to a Florida entity counts as local wherever they live, so these shares are a floor under outside ownership, not a count of it.
People stay a while. The median house has been held 8.7 years, and condo units show a median hold of 8.9 years, across the 1,276 houses and 5,609 condo units with a recorded transfer. 23.4% of houses have not changed hands in twenty years, and 9.2% in thirty. Every hold length is measured to the last transfer the county had recorded, dated February 13, 2026, which is 7.3 months before the as-of date, so each one runs short by about that gap.
Who holds Key Biscayne homes and for how long, as of September 23, 2026. Shares are worked on 1,281 houses and 5,621 condo units, and hold lengths on the parcels with a recorded transfer.
| Measure | Houses | Condo units |
|---|---|---|
| Carrying a homestead exemption | 65.7% | 33.7% |
| Held by an entity, trusts included | 37.2% | 50.5% |
| Held in a trust | 15.5% | — |
| Held in corporate or LLC form | 21.7% | 37.0% |
| Owner mails to another US state | 2.7% | 6.8% |
| Median hold | 8.7 years (n = 1,276) | 8.9 years (n = 5,609) |
| Held twenty years or more | 23.4% (n = 1,276) | — |
| Held thirty years or more | 9.2% (n = 1,276) | — |
Are you paying for the land or the building on Key Biscayne?
On a Key Biscayne house you are mostly paying for the land. Land is 81.8% of the median house's just value, across the 1,277 houses where the county splits land from building, as of September 23, 2026, and it outweighs the building on 98.2% of them. A share that high usually belongs to estates on big parcels. Here it sits on a median land area of 7,838 square feet, measured across every one of the 1,281 houses rather than a sample of sales, so the value comes from where the ground is more than from how much of it there is.
The median house is assessed at $2,314,500 against a median just value of $3,083,785. Measured against living area, the median assessed value comes to $725 per square foot. That is an assessment figure, not a price per square foot a buyer pays. Rank the land first and the house second when you compare two listings here, because the building's age moves the county's valuation far less than the ground under it.
The land share describes houses on their own land and nothing else. Miami-Dade values the 5,751 condo and co-op units at one combined figure, with no land or building share. That is the county's method for these units, never a sign of a teardown, and no land figure of any kind is given for them.
The first sign of change to read here is renovation. 47.9% of houses carry an effective year later than their build year, and the effective year is the county's own marker that a house has been reworked since it went up. Most of those gaps land on round five-year steps, so the share is the county's rough estimate and is directional. Condo units show 1.2% on the same measure, which records what the county has marked rather than whether a unit has been redone inside.
Where is the redevelopment pressure on Key Biscayne?
The pressure sits in the older houses whose land carries most of their value. 25.0% of the house stock met three or more of five redevelopment conditions as of September 23, 2026. The five are a high land share, a low building value, no renovation mark, a build year before 1980 and a small house for its land, and three or more of them earns the Strong label. That share is an upper bound and not a count of houses coming down. Scored without the no-renovation condition, the Strong count falls only from 320 to 295, or 23.0%, because the candidates are mostly 1950s houses on land that dominates their value.
No condo or co-op unit is scored at all, because its single combined value carries no land share.
Vacant ground is scarce. 63 parcels of vacant residential land remain, 0.9% of the residential universe, and 79.4% of them sit behind an entity name rather than a person. Trusts are counted inside that share and are estate planning rather than investment, so only the corporate and LLC part of it points toward outside money. The median vacant parcel has been held 4.9 years, a figure that runs short by the same 7.3-month gap as every hold length on this page.
Common questions
Interested in Off-Market Listings in Key Biscayne?
Connect with our advisory desk for private parcel alerts and valuation reports.