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Listing Board: Marathon/Lower Keys

Current Price: $16,000,000

Listing Date: 2026-08-12

List Price: $16,000,000

City: MARATHON

Mile Marker: 50

Marathon Neighborhood: Sombrero

Side: Ocean

Alternate Key #: 1124222

Parcel #: 00105590000000

Zoning: RM-1 - Residential Medium - 1

Deed Restrictions: Unknown

Legal: 23 66 32 Lot 2 (Us Patent 1186533) East Sister Rock And Adjacent Bay Bottom G71-513(Ii Deed 20369) Or374-139/40 Or752-16

Taxes: 25481.52

Tax Year: 2025

Pub Sewer HkUp: No

Street #: 1

Direction: E

Street Name: Sister Rock Island

Key/Island: Marathon

State/Province: FL

Zip Code: 33050

County: Monroe

Subdivision: Misc Sombrero Area (50.0)

Area: 14 - Sombrero Area

Realtor.COM Type: Residential - Single Family

Waterfront: Yes

Control Depth: 3

Lot Size: X

Lot SqFt: 27158

Pool: Yes

Lot Sqft Source: Tax Records

Acres: 6.44

SqFt Source: Tax Records

Rentals Allowed: Yes

Style: Off Shore Island

Year Built: 1980

Living Apx SqFt: 2304

Total Bedrooms: 4

Full Baths: 3

Total Baths: 3

Remarks – Consumer: Own an entire private island in the heart of the Florida Keys. Located just ¼ mile offshore from Marathon, East Sister Rock Island offers extraordinary privacy surrounded by turquoise waters, yet remains only minutes from the mainland. The property encompasses approximately 6.5 acres, including approximately 5.8 acres of surrounding seabed that create an exceptional marine setting for snorkeling, swimming, kayaking, paddle boarding, fishing and exploring the crystal-clear waters of the Keys. At the center of the island is a beautifully updated 3-bedroom, 2-bath main residence with a detached guest house, offering over 5,000 total SF of living and entertaining space. Recent interior renovations include a beautifully updated kitchen with gorgeous countertops and modern finishes. A 12-foot-wide wraparound veranda captures panoramic water views, Atlantic sunrises and spectacular Florida Keys sunsets. Designed for the ultimate island lifestyle, the property features a waterfront pool and spa, tropical landscaping, multiple outdoor lounging and dining areas, and a 100-foot deep-water dock with ample dockage. World-class fishing, diving, snorkeling, boating and water-sports begin just outside your door. East Sister Rock is equipped for self-sufficient island living with solar and wind power, battery storage, backup generator, desalination system and substantial freshwater cistern capacity. A private helipad provides an additional point of access. Few properties offer this combination of privacy, accessibility, marine surroundings and established island infrastructure. Seller is also open to exploring select Joint Venture opportunities. Note the sale includes 99 E Ocean Drive on the mainland which has a private dock space.

Mandatory Home Owners Asc: No

1st Right of Refusal: No

Association Fee $: 0

Transient Rntl Licns: Yes

None: 1

Dock Length: 100

Dock: Wood

None: 1

Dishwasher: 1

Dryer: 1

Microwave: 1

Oven: 1

Range: 1

Refrigerator: 1

Stainless Steel Appliance(s): 1

Washer: 1

Pets Allowed: 1

Central Air: 1

Central: 1

Oceanfront: 1

Ocean View: 1

Open Water View: 1

Tile: 1

Wood: 1

Bar: 1

Built-in Cabinets: 1

Granite Counter Top: 1

Walk-in Closet(s): 1

Above Flood: Unknown

Stories: 1 Story

Impact Rstnce Window: 1

Other: 1

CBS: 1

Concrete: 1

5 Less Than 10 Acres: 1

Cash: 1

Conventional: 1

Seller Finance Psble: 1

Other Specify: 1

Satellite Dish: 1

Septic Tank: 1

Solar Power: 1

Whole House Generatr: 1

Deck: 1

Open Porch/Balcony: 1

Detached Guest Qtrs: 1

In Ground: 1

Decked: 1

Metal Roof: 1

Accordion: 1

Status: Active