For sale

$3,200,000

Est. $22,675/mo —

•

3,080

sq ft

321 & 331 9th St, Key Colony Beach, FL 33051

About this home

Turn-Key Duplex on a Wide, Deep Canal - Key Colony Beach Welcome to one of the most sought-after settings in the Florida Keys -Key Colony Beach -- a private, tucked-away island community known for its quiet streets, boater-friendly waterways, and true Keys lifestyle. This full duplex sits on a impressively wide, clean, deep canal (100 ft across), offering easy access for boats of all sizes and some of the best water views in the neighborhood. Each side of the duplex mirrors the other in quality and layout: upstairs you'll find 2 spacious bedrooms and 2 full baths, while downstairs offers a convenient pool bath plus a bonus game room/flex space with extra storage -- perfect for kayaks, fishing gear, or beach toys. Both units have been tastefully updated and fully furnished, right down to the dishes, pots, pans, and bedding. Just bring your suitcase. This property is as flexible as it is beautiful. Rent both sides for strong dual-income potential, create the ultimate family compound with room for everyone, or live in one side while renting the other for built-in income. However you use it, you're getting two turn-key homes in one of the safest, most tranquil pockets of the Florida Keys. Located just minutes from open water, world-class fishing, and the laid-back charm Key Colony Beach is known for -- this is Keys living at its most effortless. Two homes. One incredible canal. Endless possibilities. SELLING ONLY AS DUPLEX - will not split them Contact Dawn McComish, P. A. -- The Singing Realtor® -- for a private showing.

Single-familyProperty Type

1988Year Built

8,250 sq ftLot Size

$1,039Price/Sq.Ft.

Listed by Dawn McComish • LPT Realty, LLC

Listing updated: Aug 20, 2026 at 09:07pm

Redfin checked: a few seconds ago

•Source:FLKMLS #621036

Payment calculator

$22,675 per month

Principal and interest$16,817

Property taxes

$1,164

HOA dues

Home insurance

$4,693

Utilities

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Open houses

No upcoming open houses.

Nearby open houses (3)

Around this home

Schools

K - 12
Preschool & daycare

Stanley Switlik Elementary School

Public PreK-5 • Assigned • 4.6mi

5/10

Marathon School

Public 6-12 • Assigned • 3.7mi

5/10

Provided by GreatSchools

Lifestyle

Provided by Walk Score and Local Logic

Offer insights

321 & 331 9th St · $3,200,000

Strong offer

$3.2M and above

75% chance or better to win

Why $3.2M+ is a strong offer

DAYS ON MARKET

The average home goes pending in 133 days.

SALE-TO-LIST

Most homes are selling 6% below list price.

About offer insights

Property details

Interior
Exterior
Finance

Kitchen

Bathroom

Bedroom

Living

Dining

Interior features
Smoke alarms
Impact-resistant windows and doors
Furnished
Sun/Florida room

Bathrooms
4 full bathrooms
2 half bathrooms

Kitchen
Stainless steel appliances
Microwave
Oven
Refrigerator
Dishwasher

Laundry & utility
Washer
Dryer

Flooring
Tile flooring
Laminate flooring

Heating & cooling
Central A/C

Sale and tax history for 321 & 331 9th St

Sale History
Tax History

Date

Event

Price

FLKMLS #621036

Aug 20, 2026

Listed

$3,200,000

$1,039/sq ft

MARMLS #A11245546

Sep 22, 2022

Sold

$1,232,610

$400/sq ft

Aug 24, 2022

Pending

—

Aug 17, 2022

Price Changed

$1,249,000

$406/sq ft

Jul 22, 2022

Listed

$1,279,000

$415/sq ft

Beautiful gem in the highly sought after Key Colony Beach! This rare large half duplex is ready to be a vacation rental or permanent residence for new buyers! This property has an abundance of amazing features, here are a few: 37.5' dock with a 10,000lb. Boat lift, newly remodeled beautiful kitchen with granite countertops and full granite backsplash, large master bedroom with walk-in closet, new woven wood slat fencing around property to secure privacy while you enjoy private garden with mature landscaping and a large covered rear patio with bench swing and multi-jet 6 person spa. Boaters - This property is less than 3 mins from Vaca Cut allowing you to enjoy Gulf or Atlantic, easily!!! Property comes fully furnished and is move in ready!

FLKMLS #601627

Sep 22, 2022

Sold

$1,232,610

$400/sq ft

Aug 21, 2022

Contingent

—

Aug 17, 2022

Price Changed

$1,249,000

$406/sq ft

Jun 30, 2022

Listed

$1,279,000

$415/sq ft

+29

Beautiful gem in the highly sought after Key Colony Beach! This rare large half duplex is ready to be a vacation rental or permanent residence for new buyers! This property has an abundance of amazing features, here are a few: 37.5' dock with a 10,000lb. Boat lift, newly remodeled beautiful kitchen with granite countertops and full granite backsplash, high ceilings, large master bedroom with walk-in closet, new woven wood slat fencing around property to secure privacy while you enjoy private garden with mature landscaping and a large covered rear patio with bench swing and multi-jet 6 person spa. This large half duplex feels like a single family home when inside! 1,540 sqft. of living space upstairs and an additional 496 sqft. of air conditioned storage downstairs with full bathroom, leaving you with over 2,000 sqft of air conditioned space! The garage also has a workshop area plus a sink. Boaters - This property is less than 3 mins from Vaca Cut allowing you to enjoy Gulf or Atlantic, easily!!! Property comes fully furnished and is move in ready!

Public Records

Jun 22, 2016

Sold

$610,300

$198/sq ft

FLKMLS #568862

Jun 10, 2016

Sold

$610,250

$198/sq ft

Nov 3, 2015

Listed

$669,000

$217/sq ft

FLKMLS #507414

Jun 12, 2001

Sold

$380,000

$123/sq ft

Jun 12, 2001

Listed

$380,000

$123/sq ft

Year

Property tax

Land + Additions

Assessment*

2025

$10,496 (−4.3%)

$486,750 + $582,394

$1,069,144

2024

$10,962 (+8.0%)

$478,500 + $611,332

$1,089,832

2023

$10,148 (+97.6%)

$474,375 + $526,115

$1,000,490

2022

$5,136 (−0.7%)

2021

$5,172 (+4.7%)

2020

$4,940 (−8.5%)

$247,500 + $256,950

$504,450

2019

$5,401 (+3.9%)

$247,500 + $256,950

$504,450

2018

$5,196 (+0.2%)

$247,500 + $262,827

$510,327

2017

$5,183 (+34.9%)

$247,500 + $275,037

$522,537

2015

$3,843 (−1.6%)

$247,500 + $272,059

$519,559

2014

$3,907

Public record

Public record
Permits

Beds

Baths

Stories

Lot width

—

Lot depth

—

Lot size

8,250 Sq. Ft.

Year renovated

2013

Finished Sq. Ft.

1,540

Unfinished Sq. Ft.

—

Total Sq. Ft.

1,540

Year built

1988

Style

Single Family Residential

County

Monroe County

APN

0566 33 00075560000000

Parking Spaces

—

Basement

—

Accessible

—

HOA Dues

—

Garage

—

Features

—

Last updated by owner on Jul 10, 2026.

Climate risks

1/10 Flood Factor

Minimal risk of a flood reaching the building in the next 30 years

1/10 Fire Factor

Unlikely to be in a wildfire in next 30 years

Heat Factor

We're working on getting current and accurate heat risk information for this home.

10/10 Wind Factor

99% chance of strong winds in next 30 years

1/10 Air Factor

0 unhealthy days expected this year, 0 days in 30 years

Provided by First Street

Historical weather

Key Colony Beach, FL • 33051

Average low and high temperatures (°F)

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Sun exposure

94/ 100

Exceptional sunlight

Sunscore

There appears to be minimal shading by surrounding buildings, terrain, and vegetation.

9.5 hrs

7 hrs

JuneDecember

Provided by Shadowmap

Redfin Estimate for 321 & 331 9th St

$3,027,025

$173K under list price of $3.20M

Nearby comparable homes

The Redfin Estimate uses 6 recent nearby sales, priced between $1.1M to $3.4M.

SOLD JUN 16, 2026
$3,430,000 Last sold price
4 beds4 baths3,680 sq ft
261 12th St, Key Colony Beach, FL 33051
$107/sq ft
1 year newer
SOLD JUN 12, 2026
$1,900,000 Last sold price
2 beds2 baths1,705 sq ft
220 15Th Cir, Key Colony Beach, FL 33051
$75/sq ft
larger lot
2 years newer
SOLD MAY 22, 2026
$1,100,000 Last sold price
3 beds3 baths1,511 sq ft
351 8Th St, Key Colony, FL 33051
$311/sq ft
smaller lot
18 years older
SOLD JUN 30, 2026
$3,200,000 Last sold price
4 beds4 baths2,649 sq ft
1240 Coury Dr, Key Colony Beach, FL 33051
$169/sq ft
larger lot
2 years newer
SOLD JUL 17, 2026
$1,070,000 Last sold price
3 beds3 baths1,945 sq ft
96 Avenue C #6, Marathon, FL 33050
$489/sq ft
smaller lot
14 years newer
SOLD APR 9, 2026
$3,250,000 Last sold price
3 beds3 baths2,600 sq ft
781 9Th St, Key Colony Beach, FL 33051
$211/sq ft
larger lot
11 years older

Rental earnings

Est. $3,133 per month, based on comparable rentals

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