| R.J.D. Ltd. | Harlow Common Harlow | 1993 |
| R.L. Calder Ltd | Dunfermline | 2025 |
| R.L.K. Services Limited | Camborne | 2005 |
| R.Mccreesh Ltd | Newcastle Upon Tyne | 2017 |
| R24 Recruitment Ltd | Stockport | 2019 |
| R4FFN Solutions Limited | Aberdeen | 2023 |
| R500 Greenmin Limited | London | 2019 |
| Raah Petroleum Liaison Ltd | Cardiff | 2019 |
| RAB Energy Limited | Perth | 2019 |
| Racer Association | Kenilworth | 2019 |
| Radegast AIS Ltd | London | 2017 |
| Radon Defence Limited | Canvey Island | 2025 |
| Raedan Engineering Ltd | Retford | 2011 |
| Raes Energy Ltd | Westerham | 2020 |
| Rafms Trading Ltd | Stockton-On-Tees | 2018 |
| Rahoffshore Ltd | Bacup | 2025 |
| Raid Services Ltd | Kilmarnock | 2018 |
| Rail Stone Solutions Limited | Nuneaton | 2016 |
| Rainbow Car Spar Limited | Godalming | 2012 |
| Raiyan Consulting Limited | Stockport | 2011 |
| RAJ Boss Ltd | London | 2022 |
| Rajaccess Ltd | Dingwall | 2021 |
| Rajeda Limited | Whitby | 2012 |
| Rakcas Ltd | Norwich | 2018 |
| Ralston Well Services Ltd | Peterhead | 2024 |
| Ramsay Energy Ltd | Montrose | 2019 |
| Ramsdale Farm Ltd | Scarborough | 2012 |
| Rand Corp Limited | London | 2008 |
| Ranger Consultants Limited | Skelmorlie | 1994 |
| Raphael Energy Group Limited | London | 2016 |
| Raphael Energy Limited | London | 2017 |
| Raphael Resources Limited | Lutterworth | 2019 |
| Rapid Asphalt Products Limited | Coalville | 2019 |
| Rapid OIL International Ltd | London | 2024 |
| Rapid OIL Production Ltd | Bristol | 2015 |
| Raptor Machinery Global Sourcing Limited | Wishaw | 2018 |
| Rare Earth Elements Group Ltd | London | 2023 |
| Rare Earth Technology Ltd | Hook End | 2011 |
| Rare Earths Greenland Ltd | London | 2025 |
| Rasd Developments Limited | London | 2023 |
| Rasmef Services Ltd | Aberdeen | 2016 |
| RAT Solutions Limited | Bideford | 2012 |
| Rathlin Energy (UK) Limited | London | 2008 |
| Rator Global Limited | Birmingham | 2016 |
| Ratss Ltd | Holmfirth | 2011 |
| Raven Plant Hire Limited | Newry | 2013 |
| Ravendale Completions Ltd | Montrose | 2011 |
| Ravenna Quarries & Concrete Products Ltd | Aberdeen | 2023 |
| Rayel Ltd | Feltham | 2012 |
| Raymodaw Services Limited | Milton Keynes | 2014 |
| Raymond Brown Quarry Products Limited | Eastleigh | 2017 |
| Rayong International Investment Limited | Cambridge | 2023 |
| Rays DP Marine Services Limited | London | 2022 |
| RB O&G Services Ltd | Cheltenham | 2017 |
| RB Services Northwest Limited | Wigan | 2025 |
| RB Well Services Ltd | Montrose | 2009 |
| RC PPS Ltd | Blyth | 2023 |
| RC Well Intervention Ltd | Lowestoft | 2023 |
| RCF Commodities Trading Co. (UK) Limited | Dunstable | 2022 |
| RCO Contracting Limited | Thornton Cleveleys | 2013 |
| Rcpmd Limited | Hereford | 2022 |
| RD Risk Control Ltd | Neath | 2025 |
| RDH Offshore Limited | Great Yarmouth | 2026 |
| RDH Services Ltd | Glasgow | 2018 |
| RDW Consulting Ltd | London | 2024 |
| REA Access Ltd | Middlesbrough | 2018 |
| Reabold North Sea Limited | London | 2022 |
| Reabold Southern North Sea Limited | London | 2012 |
| Reach Coal Seam GAS Limited | Aberdeen | 2008 |
| Reach Energy Limited | Aberdeen | 2011 |
| Real Mining Consultants Ltd | Scarborough | 2022 |
| Realstone Ltd | Newcastle Upon Tyne | 2017 |
| Rebtech Solutions Ltd | York | 2023 |
| Reclaym Limited | St. Austell | 2000 |
| Recls Limited | Whitby | 2013 |
| Recon Esco Trading Ltd | London | 2025 |
| Recr Limited | Stoke-On-Trent | 2025 |
| Recycled in Orsett Limited | Orsett | 2007 |
| Recycoal Limited | Tewkesbury | 2010 |
| Red Bridge Metering Services Ltd | Inverkeithing | 2022 |
| Red Dragon Geological Limited | Brechin | 2016 |
| Red Dragon Plant Limited | London | 2019 |
| Red Leopard Holdings PLC | London | 2004 |
| Red Mantle Aggregates Limited | Aberdeen | 2010 |
| Red Mantle Recycling Ltd | Aberdeen | 2026 |
| Red Rock Resources PLC | London | 2004 |
| Red Stone Drilling Limited | Banchory | 2006 |
| Redbeck Partners Ltd. | Cranleigh | 2016 |
| Redcar Welding Ltd | Redcar | 2019 |
| Redland Limited | Birmingham | 1914 |
| Redline Synergy & System Limited | London | 2020 |
| Redman Drilling Services Limited | Whitby | 2007 |
| Redmans Sand Limited | Wareham | 2016 |
| Reecewood Ltd. | Yarm | 2009 |
| Reflection Marine UK Limited | Gatwick | 2018 |
| Regius Gold Limited | London | 2016 |
| Rego Exploration Limited | Newton Abbot | 2015 |
| Reid Bros Sand & Gravel Ltd | Cookstown | 2019 |
| Reignx Global Limited | London | 2026 |
| Reinco Limited | London | 2001 |