Underwriting A South Beach Short‑Term Rental Purchase

Buying a South Beach place you can enjoy and rent out sounds simple until you run into zoning maps, condo bylaws, and lender rules. You want lifestyle flexibility, steady bookings, and a clean paper trail that stands up to underwriting. In this guide, you’ll learn how to confirm what is legal, model revenue and expenses with South Beach realities, and pressure test the deal before you write the offer. Let’s dive in.

Start with legality

Before you look at furniture packages or projected nightly rates, confirm that the specific address allows short stays. Miami Beach restricts rentals under six months and one day in many residential areas. Use the city’s lookup to see if your building or parcel is in an approved zone and review the compliance steps outlined there. Start with the City of Miami Beach’s Practice Safe Renting page to verify zoning and eligibility.

If the address checks out, the City requires a Certificate of Use and a Business Tax Receipt to operate a short‑term rental. The application typically asks for a recent letter from the association confirming that short‑term rentals are permitted for the unit. Operating without the required approvals can trigger fines and even guest evictions, and the city has enforced nuisance and party rules in high‑profile actions. Review the city’s Certificate of Use process and recent enforcement updates so you understand expectations.

Condo and HOA rules are equally important. An association can restrict or ban short‑term rentals by amendment, but Florida law limits how some new restrictions apply to owners who bought before the change. The association’s recorded documents, any rental caps or minimum terms, and the timing of amendments all matter. Study the governing documents and consult the association’s estoppel to confirm what applies to your unit.

State rules also come into play. If you rent an entire unit more than three times per year for fewer than 30 days, or advertise it that way, you may need a Florida DBPR vacation‑rental license. City approvals are separate from state licensing, so plan for both if required.

Licensing and taxes

Florida imposes a 6% state sales tax on transient rentals that are six months or less. In Miami‑Dade, local option tourist, convention, or resort taxes are layered on top and vary by jurisdiction. Combined rates change by municipality, and platform collection practices can differ by tax type. Verify current state and local rates for each booking and register the proper accounts so you can remit what is not collected by platforms.

Model revenue conservatively

South Beach earns different numbers than the broader Miami‑Dade market, and results vary by building, view, and season. Recent vendor snapshots for Miami Beach show market‑level occupancy in the mid‑60% to high‑60% range with ADRs in the low to mid‑$200s, while South Beach subsets and luxury niches push ADRs higher. Treat these as ranges, not promises, and use multiple data sources to triangulate.

Use unit history first

If the seller can provide two years of actual statements for the unit, start there. Ask for platform payout reports, owner P&Ls, and tax filings. Unit‑level history captures building idiosyncrasies such as elevator access, parking, and noise that market averages miss.

Build three scenarios

If there is no unit history, pull nearby comps from several dashboards and hosts in the same building or street. Create three cases:

• Conservative: occupancy 45% to 55% and ADR 20% to 30% below recent market medians.
• Base: occupancy 60% to 70% with ADR near the market median.
• Upside: occupancy 70% to 80% with event‑week ADR premiums.

Tools that report Miami Beach and South Beach segments can help you bracket assumptions. For example, Airbtics shows roughly 69% occupancy and ADR near $216 for Miami Beach overall, while South Beach and boutique luxury subsets can run higher ADRs with variable occupancy. StaySTRA highlights stronger winter and spring performance, and it publishes building and neighborhood snippets you can compare to your target.

Account for seasonality

South Beach is highly seasonal. Peak demand usually runs November through April, with major events like Art Basel driving spikes. Summer and the heart of hurricane season tend to see lower ADRs and thinner occupancy. Build a month‑by‑month model that flexes both rate and nights stayed so you can forecast cash flow and reserve needs.

Budget all expenses

Great ADRs can be erased by costs you did not model. Capture each of these line items in your pro forma:

• Platform and booking fees. Budget 3% to 5% of guest charges if these are not absorbed by your manager.
• Management. Expect 10% to 35% of gross revenue depending on whether you choose a marketing‑only host assist or a full‑service manager with 24/7 support.
• Cleaning and turnover. Per‑stay fees often range from $75 to $250 or more depending on size and service level. Luxury beachfront units tend to sit at the higher end.
• Utilities and supplies. Power, A/C, water, Wi‑Fi, cable, linens, and consumables are owner costs in most STR setups. Miami’s climate makes A/C a major driver.
• HOA dues. South Beach condos can have material monthly fees. Confirm what is included, how utilities are handled, and whether there are upcoming increases.
• Insurance. Price a landlord or STR‑endorsed policy and flood insurance if required by lender or location. Some carriers exclude short‑term rentals without the correct endorsement.
• Taxes and filings. Include the 6% state transient rental tax and local tourist or resort taxes, plus any local business tax obligations. Track whether platforms remit any portion so you do not double pay or miss a payment.

Plan for flood and insurance

Much of Miami Beach sits in areas with meaningful flood risk. If the property is in a Special Flood Hazard Area, lenders on federally backed loans will require flood insurance. Premiums have changed under modern rating systems, and some policies have waiting periods. Check the county’s flood resources and secure quotes early so you can underwrite accurate costs and closing timelines.

Financing realities

Your loan type and how your lender classifies the property affect down payment, rate, and underwriting. If you plan to advertise frequent short‑term rentals, a lender may treat the home as an investment rather than a second home. Investment treatment can carry higher rates, larger down payments, and stricter reserve requirements. Confirm product options with your lender at the start.

For condos, project eligibility is a gating factor. Fannie Mae and Freddie Mac review condo projects for issues such as high investor concentration, limited reserves, or pending litigation. A non‑warrantable project can push you into portfolio or DSCR loan products with different pricing. Review the condo’s eligibility early using your lender’s project screen.

Counting projected STR income in your qualification can be tricky. Some lenders want one to two years of rental receipts on tax returns to include short‑term income. Others may allow an appraiser’s market rent schedule with an expense factor. If you plan to rely on rental income to qualify, get the underwriter’s documentation list up front so there are no surprises.

Due diligence checklist

Use this sequence before you finalize price or terms:

1. Zoning and approval. Check the address on the City’s Practice Safe Renting tool. Confirm that your building or parcel is in an approved zone for short‑term rentals.
2. Association confirmation. Request a current letter or estoppel from the association stating whether short‑term rentals are allowed, any minimum lease term, caps, guest rules, and registration requirements. If wording is unclear, have counsel review.
3. City permits. Review the Certificate of Use and Business Tax Receipt requirements and timeline so you can plan for compliance.
4. State licensing. Determine whether your operation needs a DBPR vacation‑rental license based on frequency and length of stays.
5. Taxes. Register for Florida transient rental tax and the applicable local tourist or resort taxes. Confirm what your platform collects so you can remit what remains.
6. Insurance and flood. Order quotes for a policy that covers short‑term rental activity and verify flood zone status and premiums.
7. Financials and reserves. Ask the seller for 24 months of unit‑level income, plus HOA budgets, reserve studies, minutes, litigation disclosures, and special assessment history. These items influence lending, insurance, and your pro forma.

Stress‑test your deal

Run downside cases before you commit. Here are four to use on every South Beach STR purchase:

• Vacancy shock. Cut your base occupancy by 30% to 40%, or to a 45% floor, and keep cleaning and management costs tied to stays. Confirm that NOI still covers mortgage principal and interest, HOA dues, insurance, and a reserve line.
• HOA shock. Add a one‑time special assessment equal to 6 to 12 months of HOA dues. Review the latest reserve study so this input is rooted in the building’s actual needs.
• Regulatory shock. Model a scenario where your association changes its rental policy or the city tightens enforcement. Florida limits some retroactive application of condo restrictions, but timing and consent matter. Test whether a long‑term lease or sale is viable if short‑term use is curtailed.
• Lender reclassification. Recompute the numbers if your lender prices the loan as an investment with a higher rate, 15% to 25% down, and larger reserves. If you would need a DSCR or portfolio loan, update your cash‑on‑cash and DSCR under that structure.

Picking comps that translate

Not all buildings behave like the market average. A condo‑hotel with a required rental pool will not track a boutique art deco building two blocks off the beach. When you pull comps, prioritize the same building first, then immediate neighbors with similar unit mix, amenities, and rules. Use at least two data vendors and reconcile differences with what you learn from host interviews and the association’s rental patterns. Then set your conservative, base, and upside cases accordingly.

The bottom line

A South Beach short‑term rental can deliver both lifestyle and income when the legal, financial, and building‑level pieces line up. Lead with zoning and association confirmation, plug unit‑specific income and full expenses into a monthly model, and run the stress tests before you negotiate. If the numbers still work after you apply conservative assumptions, you are looking at a stronger buy.

If you want a confidential, data‑driven second opinion or help sourcing buildings that align with your strategy, schedule a private consultation with the Ben Moss Group. We will help you verify legality, coordinate due diligence, and position your offer with confidence.

FAQs

Are short‑term rentals legal at my South Beach address?

• Miami Beach allows short‑term rentals only in specific zones and buildings; use the city’s Practice Safe Renting lookup to confirm your exact parcel’s status and next steps.

What taxes apply to a South Beach short‑term rental?

• Florida charges a 6% state tax on transient rentals, and Miami‑Dade and municipalities add local tourist or resort taxes; verify combined rates and what platforms collect before each booking.

Do I need a Florida DBPR license to host in South Beach?

• If you rent the entire unit more than three times per year for fewer than 30 days, or advertise it as a transient rental, you may need a DBPR vacation‑rental license in addition to city approvals.

How do lenders treat STR income when I qualify?

• Many conventional lenders require a history of rental receipts to count STR income; others may use an appraiser’s market rent with an expense factor, so confirm documentation early with your underwriter.

What occupancy and ADR should I use in my model?

• Recent dashboards show Miami Beach‑wide medians in the mid‑60% occupancy range with ADRs in the low to mid‑$200s, while South Beach and luxury subsets can achieve higher ADRs; build conservative, base, and upside scenarios.

Can my condo association change the rules after I buy?

• Associations can amend rental rules, but Florida law limits some retroactive application to existing condo owners; the recorded documents, timing, and any owner consent determine what applies to you.