Waterfront Duplex with Boat
For Sale
$1,849,000
330-340 4th Street, Key Colony Beach, FL 33051
MULTI_FAMILY - Key Colony, FL
Property Size2,540 SF
Lot Size0.15 Acres
Price / SF$727.95
Days on Market142
Property Features for 330-340 4th Street
General Information
Property type
Residential Multi Family
Property subtype
Duplex
Zoning
R-2A - Key Colony Two Fam
Bedrooms
3
Bathrooms
4
Full bathrooms
3
Half bathrooms
1
Rooms
Bedroom 2, Bedroom 3, Bedroom 1, Bathroom 3, Bathroom 4, Bathroom 2, Bathroom 1
Parking features
Open, RV
Security features
Security System
Patio and Porch features
Porch, Patio
Pets allowed
Yes
Pool private
1
Interior features
Built-in Cabinets, Security System, Storage
Exterior features
Fencing, Lighting, Outdoor Shower, Shed, Storage
Fencing
Fenced
Appliances
Washer, Dryer, Dishwasher, Refrigerator, Range, Oven, Freezer, Ice Machine
Subdivision
Key Colony Beach (53.5)
Directions
Overseas Hwy US-1 Ocean Side turn onto Sadowski Cswy. Go to the end of Sadowski and follow the curve to the left onto E Ocean Dr to 4th Street turn left, house is on the right at 330-340.
Standard status
Active
APN
00072990-000000
Size
2,540 SF
Lot size
0.15 Acres
Taxes and HOA fees
Tax Year
2025
Tax Description
BK 3 LT 33 KEY COLONY BEACH PB3-120 SHELTER KEY OR380-643 OR455-607 OR687-619 OR1098-2040 OR1098-2046 1098-2047 OR1285-1
Tax Annual Amount
10605
Legal Description
BK 3 LT 33 KEY COLONY BEACH PB3-120 SHELTER KEY OR380-643 OR455-607 OR687-619 OR1098-2040 OR1098-2046 1098-2047 OR1285-1
Utilities
Heating system
Central
Cooling system
Central Air
Water front
1
Building Details
Year built
1971
Flooring type
Tile, Laminate
Building materials
Frame, Hardi Board Siding
Roof type
Metal
Additional Structures
Storage
Listing Agency:
Water Vista Realty, Inc.
(305) 396-7844
Listed By:
Dan Cloud · License #3144777
(305) 396-7844
Added: Apr 4
Changed: Jul 24
Last Checked: Aug 23 at 1:06AM
MLS# 619361
Copyright © 2026 Florida Keys Board of REALTORS®. All rights reserved. All information provided by the listing agent/broker is deemed reliable but is not guaranteed and should be independently verified.
Investment Insights
Based on property information with market context.
This beautifully renovated waterfront duplex includes an upper level with 2 bedrooms and 2 bathrooms and a lower level with 1 bedroom and 1.5 bathrooms. Both units feature full kitchens, and recent improvements include upgraded flooring, doors, and windows, along with a mini-split AC system and upgraded electrical in 2022. The property also features a metal roof installed in 2013, hurricane accordion and metal Bahama shutters added in 2021, and surge protection with a transfer switch for a portable generator.
Outside, the home is set up for waterfront living with a 2022 15,000-lb boat lift, a 60-foot deep-water dock, an extra-wide canal, multiple electrical outlets, and fresh water spigots. Additional exterior features include motion-activated lights with security cameras, an outdoor shower, and a heated-chilled saltwater pool added in 2022, plus a pool-cool deck patio.
Parking and storage include room for 12 cars along with space for 2 RVs and 2 boats/trailers, plus ample storage with outdoor access rooms and a shed.
Outside, the home is set up for waterfront living with a 2022 15,000-lb boat lift, a 60-foot deep-water dock, an extra-wide canal, multiple electrical outlets, and fresh water spigots. Additional exterior features include motion-activated lights with security cameras, an outdoor shower, and a heated-chilled saltwater pool added in 2022, plus a pool-cool deck patio.
Parking and storage include room for 12 cars along with space for 2 RVs and 2 boats/trailers, plus ample storage with outdoor access rooms and a shed.
Key Highlights
- Waterfront duplex on Marathon Island MM53 (Key Colony Beach, no HOA municipality), with separate upper and lower units and full kitchens in both.
- Upper unit: 2BR/2BA. Lower unit: 1BR/1.5BA—rent to separate parties at the same time or live in one and rent the other.
- Private 60 ft deep‑water dock with a new 15K lbs boat lift (2022) and extra‑wide canal; includes multiple electrical outlets and fresh water spigots.
Property Analytics
Property Profile
Current Use
Lease Details
2
Residential units
Multi-tenant
Tenancy
Location Intelligence
Trade Area within ½ mile
172
Businesses Nearby
Explore this area
Business Placement
Demographics for 33051, FL
790
Population
1,132
Households
0.7
Avg Household Size
63
Median Age
48%
College-Educated
95%
High-School Grad
0.4 sq mi
ZIP Area
1,975
Density / Sq Mi
$94,531
Median Household Income
$38,860
Median Earnings
$1,849
Median Rent
$834,800
Median Home Value
Market
Vacancy Rate% for Multifamily in South region
Questions? Ask Rey
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Frequently Asked Questions
What type of property is this?
Duplex - Renovated duplex offers two fully equipped units, with a 60-foot deep-water dock and 2022 boat lift.
Where is this duplex located?
The property is located at 330-340 4th Street Key Colony Beach, FL.
What is the asking price?
The asking price for this property is $1,849,000.
What are key features of this property?
This property features: Waterfront duplex on Marathon Island MM53 (Key Colony Beach, no HOA municipality), with separate upper and lower units and full kitchens in both.; Upper unit: 2BR/2BA. Lower unit: 1BR/1.5BA—rent to separate parties at the same time or live in one and rent the other.; Private 60 ft deep‑water dock with a new 15K lbs boat lift (2022) and extra‑wide canal; includes multiple electrical outlets and fresh water spigots.
