If you crave a Keys getaway that still feels like the Florida you remember, Grassy Key delivers. It is relaxed, low‑rise, and connected to nature, yet close to Marathon’s essentials when you need them. In this guide, you’ll learn what gives Grassy Key its Old Florida character, the second‑home profiles that thrive here, how waterfront setups differ, and the practical rules that shape ownership. Let’s dive in.
Grassy Key location and vibe
Grassy Key sits in the Middle Keys along the Overseas Highway near mile markers 57 to 60 and is part of the City of Marathon. You get quiet neighborhood streets, small marinas, and pocket parks without driving into town every day. Family and nature anchors like the Dolphin Research Center provide a reason to stay close, while Sunset Bay Park offers an easy place to catch golden hour views. The result is a slower, resident‑friendly rhythm that feels set apart from busier resort corridors.
Old Florida, defined here
When locals say Grassy Key has an Old Florida feel, they point to low‑rise homes tucked among native hammock and mangrove pockets and the absence of wall‑to‑wall high‑density buildings. You’ll notice more private homes and small, family‑run lodging sprinkled in, which keeps the streets calmer. Larger lots are common in many neighborhoods, though parcel sizes vary block by block. The island’s scale makes it simple to launch a kayak at daybreak, watch birds at sunset, and still be minutes from Marathon services.
Who thrives as owners
- Privacy and nature seekers who value sunsets, birding, kayaking, and a low‑key base. The city’s bayfront pocket park, Sunset Bay Park, is a favorite for evening light.
- Boaters and anglers who want easy bayside or canal access and nearby slips at local marinas like Grassy Key Marina.
- Retirees and seasonal residents who prefer a residential feel with quick access to groceries, services, and care in Marathon.
- Small‑group families who use a cottage or canal home as a simple gathering place, often prioritizing dockage.
Home types to expect
You will see classic Keys cottages on raised pilings, canal and bayfront homes with docks or davits, and a handful of boutique resorts or cottage clusters near the water. Oceanfront homes are rarer on Grassy Key and typically command premium pricing. Interior streets lean residential and quiet, with a mix of older homes and renovated retreats.
Bayside vs oceanfront basics
- Bayside and canal frontage often mean calmer water and easier boat access for day trips. Always verify mooring depth, turning basin width, and any recorded easements before assuming deep‑water access. Nearby slips and fuel at local marinas are a plus if your property lacks a large dock.
- Oceanfront (Atlantic) frontage offers sweeping views but may bring more exposure to surf, seawall wear, and maintenance. There are fewer continuous oceanfront streets here than on some neighboring keys, so inventory is limited.
- If you plan to add or modify a dock, be realistic about timelines and approvals. Keys projects often require state and federal reviews, plus local city or county oversight.
Docks, seawalls, permits
If a custom dock or lift is on your wishlist, plan your due diligence up front. New or replacement marine work in the Keys typically involves multi‑agency review, potential seagrass avoidance measures, and technical surveys before approval. The county outlines permitting timelines and steps for over‑water work, which helps set expectations on scope and schedule. Review the Monroe County permit process and timelines before you write a contract that assumes fast installation.
Short‑term rental rules
Grassy Key is inside the City of Marathon, so city rules apply for most properties. If you intend to rent your home short term, Marathon requires a vacation‑rental license, owner or agent training, a fire and life safety inspection, and documentation such as the state DBPR license and tax registrations. Start with the city’s official checklist for the Marathon vacation‑rental license.
If a property falls outside city limits in unincorporated Monroe County, a different set of rules applies, including an annual special vacation‑rental permit and a licensed local manager. Always confirm the jurisdiction for the exact parcel. For county‑run areas, review the Monroe County Special Vacation Rental Program.
Quick steps if you plan to rent part‑time:
- Confirm whether the parcel is in the City of Marathon or unincorporated Monroe County.
- Read the correct application checklist and gather required documents.
- Schedule and pass the fire and life safety inspection.
- Maintain a local manager if the county program applies.
Taxes for short‑term hosts
Monroe County’s Tourist Development Tax is 5 percent and is administered by the Monroe County Tax Collector. Most platforms do not automatically remit the county’s TDT, so you are responsible for registration and monthly filings. Expect to collect and remit both state sales tax and local TDT, which commonly total in the low to mid‑teens percent depending on surtaxes. Review current steps and filing details with the Monroe County Tax Collector.
Flood and insurance factors
The Florida Keys sit in coastal high‑risk flood zones, and lenders often require flood insurance. Insurers price policies based on elevation, FEMA Flood Insurance Rate Maps, and building characteristics. Before you buy, request the property’s elevation certificate, check the latest mapping status, and obtain current insurance quotes. Monroe County’s guidance on coverage and mapping is a helpful starting point: Insure Your Property.
ROGO and new building
Building in the Keys is constrained by ROGO, a rate‑of‑growth system that ties new allocations to evacuation capacity and environmental protections. If you plan to purchase a vacant lot and build, confirm the lot’s allocation status and expected timeline with local planning. Recent reporting underscores how active and sensitive these allocation discussions remain across the Keys. For background, see WLRN’s coverage of evacuation capacity and development in the Keys.
Infrastructure to watch
Marathon continues to manage wastewater and long‑term infrastructure planning. City council discussions and recent settlements around wastewater disposal have been reported, which can inform renovation and expansion decisions over time. If you are considering significant upgrades, stay current on local infrastructure news, such as this Keys Weekly summary of Marathon’s wastewater and policy discussions.
Quick buyer checklist
- Confirm jurisdiction for your exact parcel so you follow the correct rental and permitting rules.
- Check zoning and, for vacant lots or larger remodels, confirm ROGO or building allocation status and timing.
- If waterfront, request records for existing docks, seawalls, lifts, or davits, plus prior permits and surveys.
- Pull the FEMA/FIRM status and elevation certificate. Get updated flood and wind insurance quotes.
- If planning to rent, complete the Marathon or Monroe County application steps and register for state sales tax and the county TDT.
- Line up a local real estate advisor and, if you plan marine work, a Keys‑experienced marine contractor who understands agency reviews and seasonal marina demand.
Work with a boutique guide
If Grassy Key’s Old Florida pace fits your second‑home goals, you deserve a guide who blends market intelligence with on‑island practicality. You will get a boutique, concierge experience backed by national reach, plus clear guidance on docks, insurance, rental licensing, and vendor introductions. With nearly 25 years of commercial asset‑management experience and deep Middle Keys expertise, I help you buy with confidence and enjoy the Keys the way you imagined. Ready to explore homes on Grassy Key and the surrounding Middle Keys? Schedule a Tour with Tracy Chacksfield.
FAQs
Is Grassy Key part of Marathon, and why does that matter?
- Yes. Grassy Key lies within the City of Marathon, which means Marathon’s vacation‑rental licensing, inspections, and other city rules generally apply to properties on the island.
What is the difference between bayside and oceanfront ownership?
- Bayside and canal homes often have calmer water and easier boat access, while oceanfront homes can face more exposure and maintenance. Verify depth, easements, and seawall condition before you buy.
Can I add a new dock to a Grassy Key property?
- Possibly, but expect multi‑agency review, potential seagrass protections, and technical surveys. Build realistic timelines and consult a Keys‑experienced marine contractor early.
How are short‑term rental taxes handled in Monroe County?
- Hosts typically collect state sales tax and the county’s Tourist Development Tax, then file and remit as required. Registration and monthly filings are owner responsibilities.
What amenities are close by without driving into Marathon?
- You have the Dolphin Research Center, Sunset Bay Park, small marinas for slips and fuel, and a redeveloped watersports lagoon area, which make it easy to stay on island most days.
