Thinking about a vacation rental in Key Colony on Key Biscayne and wondering what a solid ROI looks like? You are not alone. With strong winter demand and premium amenities nearby, the upside is real, but the math depends on seasonality, features that move your nightly rate, and how often you turn the unit. In this guide, you will get a clear, simple framework to estimate income, control costs, and compare formats so you can buy and operate with confidence. Let’s dive in.

Key Colony and the Key Biscayne demand story

Key Biscayne is a small, affluent barrier island just offshore from Miami. Travelers come for beach access, boating on Biscayne Bay, and easy proximity to major Miami events and attractions. Key Colony sits in the heart of this, with walkable access to sand, parks, and island amenities.

This location supports a mix of stay types. Families and boating guests often book longer trips at higher price points, especially in larger or waterfront units. Smaller condos can see more frequent, shorter leisure stays. Your plan should match your unit type to the demand you want to capture.

Seasonality you can plan around

Key Biscayne runs on a clear seasonal rhythm that shapes both occupancy and pricing.

• High season: mid December through April. Expect your best occupancy and ADR during winter visitors, holiday weeks, and spring break.
• Shoulder months: May and November. Demand is steady and pricing is flexible.
• Low season: June through October. Leisure demand softens and guests are more price sensitive due to summer and hurricane season.
• Event spikes: Major Miami events like the Miami Boat Show, Ultra, Art Basel, and big sports weekends can boost short booking windows and support higher minimums.

For annual planning, remember that the year is a weighted mix of very high winter nights and softer summer nights. Multiply high-season ADR gains by fewer peak nights than the long off-season to estimate realistic annual revenue.

What lifts ADR in Key Colony

Not all features are equal in this submarket. The right amenities can materially raise both ADR and booking probability.

Waterfront views

Unobstructed water or bay views are often the single strongest ADR differentiator. When you compare comps, split waterfront versus non-waterfront within the same bedroom count to see the uplift.

Private dock or slip access

Dockage is rare and commands a premium with boating guests. It can increase ADR and encourage longer stays. Factor in added costs such as insurance, maintenance, and any slip or permitting requirements.

Private or community pool

Pools add family-friendly value. Private pools typically beat community pools on rate, especially for single-family homes. In condos and townhomes, community pools still help attract bookings.

Bedrooms, baths, and sleep flexibility

More bedrooms and smart sleep layouts broaden your audience and justify higher nightly pricing. Larger homes also require higher cleaning and linen budgets, so plan accordingly.

Outdoor living, parking, and comfort

Private outdoor space, shaded seating, reliable A/C, and on-site parking are essentials for premium positioning. Invest in quality photos and responsive service to lift realized rates and occupancy.

How to quantify uplift

Build a tight comp set from the same island, same bedroom count, and similar house rules. Compare median ADR and occupancy across key features. Use seasonal pricing curves rather than a single annual ADR so your model reflects reality.

Cleaning cadence and turn costs

Cleaning is a real margin lever because it is a per-stay cost. Shorter stays mean more turns and more expense, even when you charge a cleaning fee.

• Typical cleaning ranges per turnover: small condo roughly 75 to 150 dollars; 3-plus bedroom or waterfront homes roughly 150 to 400 dollars. Add linen service if outsourced.
• More bathrooms, outdoor sand cleanup, and higher guest counts drive cost.
• Your cleaning fee may not fully cover the true per-turn expense. Model the difference so it does not surprise you.

Length of stay drives overhead

Average length of stay sets your annual turn count. A 4-night LOS could mean up to around 91 turns at full occupancy. A 7-night LOS could bring that down to roughly 52 turns. Fewer turns lower your per-night overhead.

Set minimums by season

You can reduce turns and protect margins with longer minimums in the low season, then allow shorter stays during peak weeks when ADR is highest. Test and refine to fit your comp set and goals.

Operating costs that shape ROI

Beyond cleaning, these line items often swing returns the most in Key Biscayne.

• Management fees: Full-service managers commonly charge about 15 to 35 percent of gross rental revenue. Self-managing can lower fees but increases your time commitment.
• Utilities and consumables: Expect higher A/C use in coastal settings. Budget for electricity, water, internet, streaming, and guest supplies. Private pools add service and heating costs.
• HOA rules, dues, and insurance: Many buildings restrict short-term rentals, set minimum stay lengths, or cap the number of rentals. Insurance for short-term use is often higher than long-term policies. Dock ownership or usage can require additional coverage.
• Taxes and compliance: Florida transient rental and sales taxes apply, along with any required licensing or registrations. Model these as a percent of revenue and plan for time or service costs to manage filings.
• Maintenance and reserves: Salt air accelerates wear on metal, HVAC, outdoor furniture, and linens. Docks require recurring maintenance. Budget realistic reserves for replacements and repairs.

Build a simple ROI model

You can estimate performance with a straightforward template. Start with these inputs.

• ADR by season and an annualized estimate
• Occupancy rate
• Average length of stay and the resulting turns per year
• Cleaning cost per turn and the portion you pass through to guests
• Management fee percentage
• Variable costs per booked night
• Fixed annual costs such as insurance, HOA, property taxes, internet, pool and landscaping
• Capital reserve as a fixed dollar amount or percent of revenue
• Transient and sales tax as a percent of revenue

Then apply simple formulas.

• Nights booked per year = 365 times occupancy rate
• Gross rental revenue = ADR times nights booked
• Total turns per year = nights booked divided by average length of stay
• Annual cleaning expense = turns per year times cleaning cost per turn minus any cleaning fees collected from guests
• Management fee = gross rental revenue times management fee percent
• Net operating income from rentals = gross revenue minus management, net cleaning, variable costs, fixed costs, and taxes
• Cashflow to owner = NOI minus mortgage debt service if financed

Worked example for context

Below is an illustrative example to show how the math aggregates. Replace inputs with local comps and current regulations before making decisions.

• Inputs
  • ADR: 450 dollars
  • Occupancy: 60 percent, which is 219 nights
  • Average length of stay: 5 nights, which is about 44 turns
  • Cleaning cost per turn: 200 dollars paid to cleaner
  • Cleaning fee charged to guest: 150 dollars per booking
  • Management fee: 25 percent of gross
  • Variable costs: 15 dollars per booked night
  • Fixed annual costs: 18,000 dollars
  • Transient plus sales taxes: 12 percent of gross
• Calculations
  • Gross revenue: 450 times 219 equals 98,550 dollars
  • Cleaning revenue collected from guests: 150 times 44 equals 6,600 dollars
  • Cleaning expense: 200 times 44 equals 8,800 dollars, so net cleaning cost is 2,200 dollars
  • Management fee: 25 percent times 98,550 equals 24,637.50 dollars
  • Variable costs: 15 times 219 equals 3,285 dollars
  • Taxes: 12 percent times 98,550 equals 11,826 dollars
  • Net operating income before fixed costs: 98,550 minus 24,637.50 minus 2,200 minus 3,285 minus 11,826 equals 56,601.50 dollars
  • Net operating income after fixed costs: 56,601.50 minus 18,000 equals 38,601.50 dollars

Use this structure to test sensitivity. Change ADR, occupancy, or LOS and watch how turns, cleaning, and management fees move your bottom line.

Single family vs half-duplex or condo

Both formats can work in Key Biscayne. Your choice should align with capital, risk tolerance, and operational goals.

Single family homes

• Pros: Privacy, outdoor space, and the option for private pools or docks. These often command higher ADR and attract longer family or boating stays.
• Cons: Higher maintenance, pool and landscaping costs, larger insurance premiums, and higher cleaning per turn. Purchase price is typically higher and off-season occupancy can be more variable.
• Key ROI drivers: Dockage, private pool, bedroom count, and positioning for multi-family groups.

Half-duplex, townhouse, or condo

• Pros: Lower purchase price per unit and shared amenities such as a community pool or security. Easier to scale multiple units and batch operations like cleaning and linen service.
• Cons: HOA restrictions can limit short-term rentals or set minimum stays. With smaller units and shorter bookings, turnover cost per revenue dollar can be higher than a single family home.
• Key ROI drivers: HOA friendliness to rentals, efficient operations across units, and location within walking distance to beaches and parks.

Directionally, waterfront single family homes with docks tend to deliver the highest gross revenue potential in this submarket. Smaller condos or duplex halves can still produce attractive returns when the building permits short-term rentals, amenities are strong, and costs are managed tightly.

Your next steps

• Pull a comp set: Use active Key Biscayne listings to map seasonal ADRs and minimums for your bedroom count and amenity stack.
• Confirm rules: Check municipal code and HOA bylaws for registration, licensing, minimum stays, and any rental caps or restrictions.
• Price for seasons and events: Map mid December through April peaks and plan higher minimums around major Miami events that impact island demand.
• Nail your turn plan: Set LOS and minimums that balance occupancy and cleaning overhead. Line up reliable cleaners and linen service.
• Budget for coastal reality: Increase reserves for salt-air wear and dock maintenance if applicable.

If you want a custom ROI model for a specific Key Colony unit and a plan to maximize income, reach out. You will get a clear P&L view and practical steps to execute. Connect with Jessica Borraccino to get started.

FAQs

What is the peak rental season in Key Biscayne?

• Mid December through April is the high season with the strongest ADR and occupancy, supported by winter visitors, holiday weeks, and spring break.

How do Miami events affect Key Biscayne vacation rental rates?

• Large events like the Miami Boat Show, Ultra, and Art Basel can create short booking spikes that support higher ADRs and stricter minimum stays for those dates.

What features most increase ADR in Key Colony condos?

• Water views, any form of dock or slip access, pool access, higher bedroom count, quality outdoor space, and professional listing and service standards.

How do cleaning and length of stay impact ROI in Key Biscayne?

• Cleaning is a per-stay cost. Shorter stays drive more turns and raise per-night overhead, while longer minimums reduce turns and lower cost per booked night.

What management fee should I model for a Key Biscayne rental?

• Full-service short-term rental management commonly ranges from about 15 to 35 percent of gross rental revenue, depending on services and scale.

What operating costs are easy to underestimate on the island?

• Insurance for short-term use, HOA constraints, transient taxes, A/C and pool utilities, and faster replacement cycles due to salt air and any dock maintenance.