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  • Flats on First

    21 Charles St, Cambridge, MA 02141

    Apartment building
    1 bed
    Pet-friendly
    Other parking
    In-unit laundry (W/D)

    Available units

    This listing now includes required monthly fees in the total price.

    Learn more
    Unit
    , sortable column
    Sqft, sortable columnAvailable, sortable columnTotal price, sorted ascending
    420B
    1 bd, 1 ba
    767
    Now
    $3,645
    303C
    1 bd, 1 ba
    699
    Now
    $3,703
    404C
    1 bd, 1 ba
    718
    Nov 28
    $3,878
    102C
    1 bd, 1 ba
    896
    Dec 14
    $4,078
    213B
    1 bd, 1 ba
    914
    Nov 10
    $4,603

    What's special

    Patio
    In the mood for fresh air?
    A patio is a rare feature. Less than 14% of buildings in Cambridge have this amenity.
    Flats on First embodies the best of boutique living, combining the luxuries of a modern apartment community with the comforts of a close-knit neighborhood. Come home to a place of sophistication and serenity in East Cambridge.

    Office hours

    DayOpen hours
    Mon - Fri:10 am - 6 pm
    Sat:10 am - 5 pm
    Sun:Closed

    Facts, features & policies

    Building Amenities

    Community Rooms
    • Fitness Center: 24-Hour Fitness Center
    • Game Room
    Other
    • In Unit: Full-Size, High Efficiency Washer/Dryer
    Outdoor common areas
    • Barbecue: Grilling And Al Fresco Dining
    • Patio: Balconies*
    Security
    • Intercom: Butterflymx Intercom System
    Services & facilities
    • Bicycle Storage: Bike Storage
    • Package Service: 24-Hour Package Room
    View description
    • Roof Deck With City Views

    Unit Features

    Appliances
    • Dryer: Full-Size, High Efficiency Washer/Dryer
    • Washer: Full-Size, High Efficiency Washer/Dryer
    Flooring
    • Vinyl: Luxury, Wood-Grained Vinyl Flooring
    Other
    • Patio Balcony: Balconies*

    Policies

    Parking
    • Garage: Controlled Access Parking Garage
    • Parking Lot: Other
    Pets
    Dogs
    • Allowed
    • Dogs and Cats Restrictions: None
    Cats
    • Allowed
    • Dogs and Cats Restrictions: None

    Special Features

    • Co-working Spaces
    • Community Kitchen And Dining
    • Direct Access Entry*
    • Gourmet Kitchens With Stainless Steel Appliances
    • Groom Room
    • Landscaped Courtyards With Outdoor Seating
    • Open Air Amphitheater
    • Open Floor Plans
    • Outdoor Lounges With Fire Pits
    • Pet Friendly
    • Quartz Countertops
    • Schlage Smart Locks
    • Social Spaces With Complimentary Wifi
    • Stand-up Showers*
    • Walk-in Closets*

    Neighborhood: East Cambridge

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    • Walkable Streets
      Pedestrian-friendly layout encourages walking to shops, dining, and parks.
      Transit Access
      Convenient access to buses, trains, and public transit for easy commuting.
      Dining Scene
      From casual bites to fine dining, a haven for food lovers.
      Green Spaces
      Scenic trails and gardens with private, less-crowded natural escapes.
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    East Cambridge’s 02141 blends historic rowhouses and a strong Portuguese and Brazilian heritage with shiny new Cambridge Crossing and waterfront greens along the Charles. Expect four true New England seasons—crisp springs, warm summers, colorful falls, and snowy winters—plus breezes near North Point Park and Lechmere Canal Park. Daily life is walkable and bike friendly, with Lechmere Station on the Green Line, Bluebikes docks, and quick links to Kendall/MIT, downtown Boston, and I-93. Food and coffee range from neighborhood favorites like The Helmand, Tatte, and Curio Coffee to chef-driven spots at CX (The Lexington, Geppetto, Cafe Beatrice), plus Lamplighter’s CX brewery. Errands are easy with Target and shops at CambridgeSide and local markets along Cambridge Street; larger grocers sit a short ride away. Residents jog the river paths, relax on the CX Common, and enjoy community festivals that reflect the area’s roots. The mix spans young professionals, grad students, and long-time families, and it’s notably pet friendly. Per Zillow Market Trends, recent median asking rent is about $3,800, with most listings around $3,000-$5,800.

    Powered by Zillow data and AI technology.

    Areas of interest

    Use our interactive map to explore the neighborhood and see how it matches your interests.

    Travel times

    Walk, Transit & Bike Scores

    97 / 100
    Walker's Paradise
    86 / 100
    Excellent Transit
    98 / 100
    Biker's Paradise

    Nearby schools in Cambridge

    GreatSchools rating

    Frequently asked questions

    What is the walk score of Flats on First?

    Flats on First has a walk score of 97, it's a walker's paradise.

    What is the transit score of Flats on First?

    Flats on First has a transit score of 86, it has excellent transit.

    What schools are assigned to Flats on First?

    The schools assigned to Flats on First include Kennedy-Longfellow School, Vassal Lane Upper School, and Cambridge Rindge and Latin School.

    Does Flats on First have in-unit laundry?

    Yes, Flats on First has in-unit laundry for some or all of the units.

    What neighborhood is Flats on First in?

    Flats on First is in the East Cambridge neighborhood in Cambridge, MA.

    Does Flats on First have virtual tours available?

    Yes, 3D and virtual tours are available for Flats on First.

    Your dream apartment is waitingOne new unit was recently added to this listing.
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