For sale

$3,200,000

Est. $23,539/mo —

•

3,080

sq ft

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

About this home

SELLER FINANCING AVAILABLE - 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

Multi-familyProperty Type

1988Year Built

8,250 sq ftLot Size

$1,039Price/Sq.Ft.

Listed by Dawn McComish P.A. McComish • LPT Realty, LLC

Listing updated: Nov 3, 2026 at 07:28pm

Redfin checked: a few seconds ago

•Source:FLKMLS #621036

Payment calculator

$23,539 per month

Principal and interest$17,681

Property taxes

$1,164

HOA dues

Home insurance

$4,693

Utilities

Add

5 minutes to get started. No credit impact.

Affordability tools

See this home in person

We'll connect you with a local agent to show you this home, answer your questions, and assist you on your buying journey.

Next available tour time: Today

Open houses

No upcoming open houses.

Nearby open houses (5)

OPEN TODAY, 12PM TO 3PM
$799,000
3 beds2 baths— sq ft
385 Orange Ave, Grassy Key, FL 33050
Parking • Pool • Built 1991
(954) 545-5583
OPEN TODAY, 12PM TO 1PM
$1,195,000
3 beds3 baths1,500 sq ft
315 E Ocean Dr, Key Colony Beach, FL 33051
3,305 sq ft lot • Pool • Built 2001
OPEN TODAY, 12PM TO 3PM
$199,000
Land— sq ft
319 Tuskegee St, Marathon, FL 33050
Listed 260 days
(954) 545-5583
OPEN TODAY, 1PM TO 3PM
$899,000
3 beds3 baths1,929 sq ft
1133 W Ocean Dr #6, Key Colony Beach, FL 33051
$2,436 HOA • Pool • Built 1982
OPEN NOV 21, 11AM TO 1PM
$775,000
2 beds2 baths1,276 sq ft
2240 Harbor Dr, Marathon, FL 33050
9,649 sq ft lot • 2 parking spots • Built 1956

Around this home

Schools

K - 12
Preschool & daycare

Stanley Switlik Elementary School

Public PreK-5 • Assigned • 4.6mi

4/10

Marathon School

Public 6-12 • Assigned • 3.7mi

4/10

Provided by GreatSchools

Lifestyle

Provided by Walk Score and Local Logic

Offer insights

321 & 331 9th St · $3,200,000

Strong offer

$3.16M and above

75% chance or better to win

Why $3.16M+ is a strong offer

DAYS ON MARKET

The average home goes pending in 148 days.

SALE-TO-LIST

Most homes are selling 4% below list price.

About offer insights

Property details

Interior
Exterior
Finance

Kitchen

Bathroom

Bedroom

Living

Dining

Interior features
Furnished
Smoke detectors installed
Storage space

Bathrooms
4 full bathrooms
2 half bathrooms

Kitchen
Dishwasher
Oven
Microwave
Refrigerator
Stainless steel appliances

Laundry & utility
Washer
Dryer

Flooring
Tile
Laminate

Heating & cooling
Central air conditioning

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*

2026

$10,240 (−2.4%)

$424,875 + $642,106

$1,066,981

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 Nov 12, 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)

73°

64°

75°

68°

79°

71°

81°

75°

85°

79°

87°

81°

89°

82°

90°

82°

87°

79°

84°

77°

79°

73°

77°

70°

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Sun exposure

94/ 100

Exceptional sunlight

Sunscore

This home receives average direct sun exposure in Key Colony Beach. 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

$2,942,498

$258K under list price of $3.20M

Nearby comparable homes

The Redfin Estimate uses 6 recent nearby sales, priced between $1.1M to $2.8M.

SOLD SEP 22, 2026
$2,775,000 Last sold price
6 beds4 baths3,392 sq ft
420 11th St, Key Colony, FL 33051
$221/sq ft
5 years older
SOLD AUG 7, 2026
$2,229,000 Last sold price
3 beds3 baths2,001 sq ft
641 12th St, Key Colony Beach, FL 33051
$75/sq ft
larger lot
11 years newer
SOLD APR 10, 2026
$1,340,000 Last sold price
4 beds3 baths1,813 sq ft
351 10th St, Key Colony Beach, FL 33051
$300/sq ft
4 years newer
SOLD SEP 15, 2026
$1,075,000 Last sold price
3 beds2.5 baths2,000 sq ft
180 9th St, Key Colony Beach, FL 33051
$501/sq ft
smaller lot
13 years newer
SOLD APR 24, 2026
$1,300,000 Last sold price
3 beds2 baths1,540 sq ft
270 Sadowski, Key Colony, FL 33051
$195/sq ft
smaller lot
18 years newer
SOLD APR 24, 2026
$2,400,000 Last sold price
3 beds2.5 baths2,521 sq ft
210 14Th St, Key Colony Beach, FL 33051
$87/sq ft
4 years newer

Tour for free, no strings attached

Instant answers, or connect with a local agent

Start an offer