| J Quinn Accountancy Limited | Professional & scientific | 2013 |
| J R Chimneys & Flues Limited | Construction | 2017 |
| Jasme Limited | Professional & scientific | 2012 |
| JC Animations Ltd | Professional & scientific | 2021 |
| JC Decorating and Design Ltd | Construction | 2023 |
| JCL Commercial Consulting Limited | Professional & scientific | 2024 |
| Jewellery M.O.T Ltd | Wholesale & retail | 2022 |
| JNB Office Services Limited | Professional & scientific | 2014 |
| John F Dorman Limited | Administrative & support | 2011 |
| John Garland Consulting Limited | Professional & scientific | 2010 |
| JS Security Insights Ltd | Information & communication | 2025 |
| Jurassic Auto Ltd | Wholesale & retail | 2025 |
| Jurassic Physio Limited | Health & social care | 2016 |
| Jurassic Vets Limited | Professional & scientific | 2020 |
| K Wallbridge Ltd | Professional & scientific | 2005 |
| K. D. Crellen Partnership Ltd | Professional & scientific | 2025 |
| Kairus Ltd | Professional & scientific | 2011 |
| Kapes Ltd | Wholesale & retail | 2022 |
| KBA Property Limited | Real estate | 1998 |
| Kdms Property Management Limited | Households | 2019 |
| Kennaway House Trust | Arts & recreation | 2008 |
| Kessada Ltd | Wholesale & retail | 2018 |
| Kieron Bewes Horticultural Consultant Limited | Administrative & support | 2008 |
| Kincraig (Exmouth) Management Company Limited | Households | 2000 |
| Kindle Homes Limited | Real estate | 2001 |
| Kindle Housing Limited | Administrative & support | 2000 |
| King's Court Management (Seaton) Limited | Households | 2004 |
| Kings Caravan Servicing Ltd | Wholesale & retail | 2023 |
| Kingsdown Garage Ltd | Wholesale & retail | 2018 |
| Knowle Grange Management Company Limited | Households | 1982 |
| Knowle Park (Sidford) Limited | Households | 1981 |
| L & J Corporate Limited | Financial services | 2021 |
| Land Solutions (South West) Limited | Administrative & support | 2017 |
| Langman Lettings Limited | Hospitality | 2021 |
| Langsford Barton Management Company Limited | Households | 2003 |
| Laser Lounge Sidmouth Ltd | Other services | 2024 |
| LB Tax Assist Ltd | Professional & scientific | 2023 |
| LD Renovate Limited | Construction | 2019 |
| LDC Estates Ltd | Construction | 2021 |
| LE Dragon Limited | Real estate | 1987 |
| Learning for Change Limited | Administrative & support | 1999 |
| Leatherneck Ltd | Administrative & support | 2022 |
| Leigh Cottages Management Company Limited | Real estate | 2016 |
| Lemna Limited | Real estate | 2015 |
| Lennards Court (Sidmouth) Management Co. Limited | Households | 1989 |
| LHW Consulting Ltd | Professional & scientific | 2021 |
| Lifestyle Pharmacy Limited | Wholesale & retail | 1997 |
| Lilywhites Property Limited | Hospitality | 2026 |
| Linstead Court Management Company Limited | Households | 1995 |
| Little Chart Ltd | Real estate | 2022 |
| Livonia House (Sidmouth) Limited | Real estate | 2010 |
| LKA Consultants Ltd. | Information & communication | 1996 |
| LP SD Eighty SIX Limited | Wholesale & retail | 2023 |
| Lucky PIG Productions Ltd | Professional & scientific | 2022 |
| Lulu Arver Ltd | Wholesale & retail | 2010 |
| Lybrico Limited | Financial services | 2024 |
| Lyme Disease Action | Other services | 2003 |
| M & H Service Limited | Professional & scientific | 2014 |
| M R Dury & Co Ltd | Professional & scientific | 2008 |
| Macall Investment Group Limited | Wholesale & retail | 2020 |
| MANOR41 Limited | Professional & scientific | 2012 |
| Manstone West Limited | Professional & scientific | 2003 |
| Marazion Devon Ltd | Households | 2025 |
| Marazion East Devon Ltd | Households | 2025 |
| Margaret Denver Design Limited | Wholesale & retail | 2002 |
| Marine Court (Budleigh Salterton) Management Company Limited | Households | 1991 |
| Martor Management Company Limited | Households | 2002 |
| Mary Hobley & Associates Limited | Professional & scientific | 2010 |
| Matt Weaver Limited | Hospitality | 2014 |
| Mcfarren Media Limited | Information & communication | 2025 |
| Mcshaw Opticians Limited | Wholesale & retail | 1997 |
| Meal Deal Ltd | Wholesale & retail | 2025 |
| Mefoods Limited | Hospitality | 2020 |
| MH Building Service Limited | Construction | 2014 |
| Michael Gott Limited | Mining & quarrying | 2014 |
| Midi Catering Ltd | Hospitality | 2025 |
| Milkbere Cottage Holidays Limited | Real estate | 2002 |
| Millard Cook Ltd | Real estate | 2020 |
| Millford Avenue Residents Association Limited | Households | 2023 |
| Milly Harding HR Consultancy Ltd | Administrative & support | 2024 |
| Mint Moves Ltd | Transport & logistics | 2024 |
| MLF Sidmouth Ltd | Wholesale & retail | 2015 |
| Monterey Consulting Ltd | Professional & scientific | 2025 |
| Montgomery Coates Limited | Construction | 2003 |
| Moon Drop Sidmouth Ltd | Manufacturing | 2025 |
| Moor Park (2005) Limited | Households | 2005 |
| Morcote Property Investment Ltd | Real estate | 1999 |
| Morrison Bell Trust | Arts & recreation | 2013 |
| MR Capital Consultants Limited | Administrative & support | 2014 |
| MS Electrical South-West Ltd | Construction | 2024 |
| MS Holdings (Sidmouth) Limited | Financial services | 2026 |
| Mutamayo Limited | Information & communication | 2012 |
| Myers Financial Consultancy Limited | Professional & scientific | 2015 |
| Nana's Purls Limited | Manufacturing | 2025 |
| Naturehubs South West CIC | Arts & recreation | 2025 |
| Ncts London Ltd | Education | 2019 |
| Neil Blakeman Associates Limited | Professional & scientific | 2006 |
| Neural Leap Consulting Limited | Agriculture & fishing | 2004 |
| Ngdc Limited | Professional & scientific | 2018 |
| Ninns Ltd | Hospitality | 2025 |