| Apple Tree Farm Services CIC | Umberleigh | 2020 |
| Appleby Environmental Services Limited | Ashington | 2008 |
| Appleby Farms Limited | York | 1986 |
| Appleby Game Limited | Sherborne | 2009 |
| Applebys Farm Limited | Wallasey | 2021 |
| Applecast Limited | Chorley | 2006 |
| Applecross Equestrian Limited | Droitwich | 2015 |
| Applecross Organics Limited | Strathcarron | 1995 |
| Applecross Pier Users Association | Strathcarron | 2000 |
| Appledore Turkeys Limited | Kent | 2008 |
| Appledores Farm Limited | Near Bury St Edmunds | 2014 |
| Appledunc Limited | Bristol | 2012 |
| Applegate Nurseries Limited | Sidlesham Chichester | 2003 |
| Appleton Contracting South Ltd | Alresford | 2019 |
| Appleton Family Farm Ltd | Hereford | 2020 |
| Appleton Farming Limited | Wigan | 2016 |
| Appleton Farms Limited | Martin | 1991 |
| Appleton Grange Equestrian Centre Limited | Thornton-Le-Dale | 2009 |
| Applevale Limited | Cheltenham | 2002 |
| Applewick Dairy Limited | Chippenham | 2012 |
| Appleyard Farm Ltd | Cardiff | 2017 |
| Applied Poultry Ltd | Great Chesterford | 2024 |
| Apricot Centre CIC | Totnes | 2010 |
| April Goodier Ltd | Northwich | 2013 |
| Apron Creative CIC | Shoreham By Sea | 2024 |
| APS Countryside Contracts Limited | Bolton | 2003 |
| APS Growers Ltd | Chichester | 2012 |
| APS Produce Limited | Chichester | 1997 |
| Apserv Ltd | Glasgow | 2019 |
| Apsley Farms Sales Limited | Andover | 2021 |
| Apsley Manor Farm Limited | Aylesbury | 2013 |
| APT Holdings Limited | Colchester | 2003 |
| Aptech Advisory Ltd | London | 2021 |
| Aqua Avantgarde Limited | London | 2024 |
| Aqua Botanika Limited | Torquay | 2020 |
| Aqua Bridge Farms Ltd | Heckmondwike | 2023 |
| Aqua Depot Ltd | Isleworth | 2014 |
| Aqua Ecosystems UK Ltd | Wirral | 2015 |
| Aqua Equine Ltd | Bracknell | 2025 |
| Aqua Farms Limited | Swansea | 2017 |
| Aqua Fauna UK Limited | Bury St. Edmunds | 2024 |
| Aqua Fresh Fish Limited | Greenford | 2022 |
| Aqua Innovation Limited | Inverness | 2017 |
| Aqua Lemna Group International Ltd | Louth | 2024 |
| Aqua Lemna Group Ltd | Louth | 2023 |
| Aqua Marine Developments Limited | Crumlin | 2002 |
| Aqua MED Ltd. | London | 2016 |
| Aqua Quip Scotland Ltd | Edinburgh | 2020 |
| Aqua South Ltd | Walton-On-Thames | 2026 |
| Aqua VEG Ltd | Norwich | 2023 |
| Aqua-Ting Limited | Tipton | 2025 |
| Aquabanq Management & Holding Co. Ltd | London | 2015 |
| Aquaconsult Ltd | Shetland | 2020 |
| Aquacore Solutions Ltd | Southall | 2025 |
| Aquaculture Consultancy & Equipment Limited | Bewdley | 2023 |
| Aquaculture Feeds Limited | Nantwich | 2015 |
| Aquaculture Industry Wales Ltd | Llanrhystud | 2020 |
| Aquaculture Innovations Limited | Loughborough | 2021 |
| Aquaculture Marine Services Ltd | Isle Of Skye | 2019 |
| Aquaculture Stewardship Council | London | 2012 |
| Aquaculture Transformation Limited | Sheffield | 2025 |
| Aquacultured Seafood Limited | London | 2020 |
| Aquadal Ltd | Spalding | 2025 |
| Aquaedge Solutions Limited | Fortrose | 2025 |
| Aquafarmuk Ltd | Leicester | 2019 |
| Aquafish Solutions Limited | Exeter | 2007 |
| Aquagen Scotland Ltd | Stirling | 2016 |
| Aquagronomy Limited | Thirsk | 2008 |
| Aquahelios Limited | Droitwich | 2017 |
| Aquaholics Aquatics Ltd | Peterborough | 2025 |
| Aqualand the Land of Aqua-Holics Ltd | Newcastle Upon Tyne | 2012 |
| Aqualate Castle Holdings Limited | Newport | 2022 |
| Aqualife (Leyland) Limited | Southport | 2003 |
| Aqualogy Ltd | Chatham | 2009 |
| Aquamacs (UK) Ltd | Cardiff | 2011 |
| Aquamaintain Consultancy Ltd | Crawley | 2017 |
| Aquamaintain Ltd | Crawley | 2012 |
| Aquamarine Maintenance Ltd | Ashton-Under-Lyne | 2023 |
| Aquanet Limited | Clacton On Sea | 1996 |
| Aquanzo Ltd | Roslin | 2022 |
| Aquapaws Canine Hydrotherapy and FUN Swim Ltd | Barnsley | 2022 |
| Aquapaws Canine Hydrotherapy Ltd | Pontefract | 2023 |
| Aquaponics GB Limited | Nottingham | 2020 |
| Aquaria (Grimsay) Ltd | Isle Of North Uist | 2014 |
| Aquarium Connections Ltd | Sutton | 2014 |
| Aquarium Limited | Chesterfield | 2024 |
| Aquarius Fishing Co. Limited | Muir Of Ord | 2002 |
| Aquascape Fish Imports Limited | Sutton Coldfield | 2003 |
| Aquascaping Liverpool Ltd | Liverpool | 2023 |
| Aquascience Consultancy Limited | Sheffield | 2014 |
| Aquasense (UK) Limited | Uxbridge | 2013 |
| Aquassi Ltd | London | 2025 |
| Aquasure Technical Ltd | Leeds | 2025 |
| Aquatak Limited | Bristol | 1990 |
| Aquate Limited | Nuneaton | 2026 |
| Aquatic Chalks Ltd | Grantham | 2000 |
| Aquatic Development & Consultancy Limited | Borehamwood | 2020 |
| Aquatic Excellence Limited | Upminster | 2020 |
| Aquatic Industries Limited | Kington | 2016 |
| Aquatic Maintenance Ltd | Bexley | 2013 |