SeaGlass Cove
Homes for Sale in Marathon, FL

SeaGlass Cove is a new-construction, gated oceanfront enclave of 14 residences on Grassy Key, within the city of Marathon, Monroe County (ZIP 33050), at 59720 Overseas Highway. Developed by Constellation Group, the homes rise three stories above a private beach with open-water Atlantic views, offering four- and five-bedroom floor plans of roughly 4,800+ square feet with two-car garages. Planned and marketed amenities include a resort-style pool, a pickleball court, and a private sandy beach. Pricing starts from about $3 million, and the developer states that weekly rentals are permitted. Because the community is newly delivered, there is little or no recorded resale history, so this page tracks the enclave's launch and early sales rather than an established pricing picture.

Pre-construction details are compiled from public records, builder announcements and builder listings, and are subject to change without notice; figures are deemed reliable but not guaranteed. Momentum Research figures are our own analysis. This page describes homes, pricing and community attributes, not residents.

In ZIP 33050 (Marathon), 209 homes closed in the last 12 months at a median of $799K, up 6.4% year over year, with a median 87 days on market. See the live ZIP 33050 housing market and the Monroe County market.

ZIP and county figures describe the wider market, not SeaGlass Cove specifically. Momentum Research analysis of MLS records.

The detail that makes SeaGlass Cove worth a page is its scarcity and structure. Monroe County's ROGO permit system rations new residential construction across the Keys, which is why brand-new, purpose-built ownership communities almost never appear here. SeaGlass Cove is a fixed enclave of 14 residences behind a gated entry on Grassy Key, an oceanside island inside Marathon. That fixed count matters: there is no phase two, so buyers are choosing among a small, finite set of homes rather than a rolling release.

The product itself is large for the Keys. Floor plans run four and five bedrooms across roughly 4,800+ square feet on three levels, each with a two-car garage, positioned for direct open-water Atlantic views above a private beach. Shared amenities marketed by the developer include a resort-style pool, a pickleball court, and beach access. The developer also states that weekly rentals are permitted, which is unusual in the Keys and can matter to buyers weighing personal use against rental income.

Two things should be confirmed in writing before any deposit. First, the ownership and carrying structure: whether the residences are sold fee-simple or as a condominium, and the amount and scope of the HOA or association assessment, were not published at discovery. Second, verify the rental permission in the association documents and against current Monroe County and City of Marathon vacation-rental rules, since transient-rental eligibility in the Keys is governed by specific licensing and can change. Developer disclosures note that plans, amenities, and pricing are subject to change.

For a finite, high-value enclave like this, the value of a local agent is diligence and positioning. We can pull the recorded documents to confirm whether SeaGlass Cove is fee-simple or condominium, get the association budget and assessment in writing, and read exactly how the weekly-rental permission is worded before you rely on any income assumption.

We also help you compare the remaining SeaGlass Cove homes against resale oceanfront options elsewhere in Marathon, Grassy Key, and Duck Key, so a roughly $3 million-and-up decision is underwritten on verified numbers, flood and insurance realities, and the real carrying cost, not on a brochure.

Confirm the current HOA dues, exactly what they cover, and any CDD bond or special assessment for a specific address before you offer.