| Riskend Aggregates Limited | Glasgow | 1967 |
| Rissbrook Solutions Limited | Harlech | 2024 |
| Ritchie's Offshore Services Limited | Wemyss Bay | 2014 |
| River Calder Stone Limited | Preston | 2024 |
| Riverlight Investments Ltd | London | 2023 |
| Riveron (22) Ltd | Kilmarnock | 2015 |
| Riverside Engineering UK Limited | Stockton-On-Tees | 2007 |
| Riverside Precision Materials Limited | Dinnington | 2021 |
| Riverstone Resources Ltd | London | 2024 |
| RJ Gauld Ltd | Fraserburgh | 2025 |
| RJ Harriss Mining Ltd | Sleaford | 2024 |
| RJ Mechanical Services Ltd | Stockton-On-Tees | 2024 |
| RJ Mitten & Sons Ltd | Enniskillen | 2025 |
| RJM OIL Field Services Ltd | Haverfordwest | 2013 |
| RJM Well Services Ltd | Aberdeen | 2025 |
| RJS HSE Ltd | Grimsby | 2024 |
| RJS Welding and Inspection International Ltd | Aberdeen | 2023 |
| RK Access & Rescue Ltd | Alloa | 2018 |
| RKF Services Limited | Dundee | 2019 |
| RKR Mining Limited | London | 2002 |
| RL Taylor Haulage Limited | Exeter | 1995 |
| RLH Inspection Services Limited | Leyland | 2011 |
| RLK Mining Consultants Limited | Penzance | 2018 |
| Rlndt Division Limited | Dundee | 2019 |
| RLS Marine Limited | Bootle | 2015 |
| RM Drilling Ltd | Musselburgh | 2018 |
| RM Gold (Services) Limited | Maidstone | 2010 |
| RM Services (Montrose) Ltd | Montrose | 2006 |
| RMC Explorations Limited | Edinburgh | 1960 |
| RMD Subsea Limited | Glasgow | 2012 |
| RMF Lifting Limited | Edinburgh | 2013 |
| RMM Engineering Design Limited | Aberdeen | 2007 |
| Rmri Ltd | Manchester | 2005 |
| RNK Inspection Services Ltd | Ayr | 2022 |
| RNR Energy Performance Ltd | Aberdeen | 2009 |
| ROB Stables Ltd | Montrose | 2023 |
| Robberg Resources Ltd. | London | 2015 |
| Robbie.Ski Ltd | Crook | 2025 |
| Robert Mackenzie Limited | Aberdeen | 1996 |
| Robertson Global Ltd | Aberdeen | 2013 |
| Robin Selby Valuations Limited | Dartmouth | 2019 |
| Robinson Concrete Ltd | Londonderry | 2013 |
| Robinson Energy Services Limited | Warrington | 2025 |
| Robinson Estimating and Costing Services Ltd | Merseyside | 2007 |
| Robinson Quarry Masters Limited | Newtownabbey | 1973 |
| Robinson Rowley Ltd | Doncaster | 2021 |
| Robomichael Limited | Slough | 2019 |
| Rocblast Ltd | Carrickfergus | 2007 |
| Rocdrill Limited | Lisburn | 1996 |
| Rock Drilling Tools Limited | Kirkcaldy | 1999 |
| Rock END Moor Gritstone Company Limited | Todmorden | 2011 |
| Rock Equipment Ltd | Bridgend | 2023 |
| Rock Forth Limited | Wolverhampton | 2018 |
| Rock Minerals Limited | Basildon | 2026 |
| Rock NET (Group) Ltd | Spalding | 2008 |
| Rock NET Quarries Ltd | Lincolnshire | 2007 |
| Rock NET Transport Ltd | Spalding | 2015 |
| Rock NET Works Ltd | Spalding | 2011 |
| Rock NET Zero Ltd. | Lincolnshire | 2007 |
| Rock OIL Company PLC | London | 2012 |
| Rock Result Limited | Tetbury | 2015 |
| Rock Solid Energy Solutions Ltd | Stockton-On-Tees | 2018 |
| Rockbolting Technology Limited | Derbyshire | 2004 |
| Rockdem Limited | Tavistock | 2026 |
| Rockgate Services Ltd | London | 2020 |
| Rockhopper Civita Limited | Salisbury | 2000 |
| Rockhopper Croatia Limited | Salisbury | 2015 |
| Rockhopper Exploration (Hydrocarbons) Limited | Salisbury | 2005 |
| Rockhopper Exploration (OIL) Limited | Salisbury | 2005 |
| Rockhopper Exploration (Petrochemicals) Limited | Salisbury | 2005 |
| Rockhopper Exploration PLC | Salisbury | 2004 |
| Rockhopper Mediterranean Limited | Salisbury | 2005 |
| Rockhopper Resources Limited | Salisbury | 1995 |
| Rockincolour Ltd | Ballynahinch | 2016 |
| Rocklore Drilling Services Limited | Aberdeen | 2023 |
| Rocklore Exploration Services Limited | Guildford | 2010 |
| Rockmate Limited | Nantwich | 1998 |
| Rocko Ltd | Edinburgh | 2020 |
| Rockrose (UKCS2) Limited | London | 2013 |
| Rockrose Energy Limited | London | 2015 |
| Rockrose Ukcs 10 Limited | London | 2000 |
| Rockrose UKCS15 Limited | Aberdeen | 2010 |
| Rockrose UKCS4 Limited | London | 1990 |
| Rocktech Group Ltd | Wallsend | 2024 |
| Rocky Mountain Resources Limited | London | 2020 |
| Roco (Blyth) Limited | Blyth | 2013 |
| ROD Welding Limited | Aberdeen | 1999 |
| Rogan Drilling Services Limited | Whitehaven | 2012 |
| Roger White Tailings Consultant Ltd | Maidenhead | 2020 |
| Rolling Road Resources Ltd | Weybridge | 2018 |
| Rolling Trade Ltd. | Edinburgh | 2005 |
| Romar International Ltd. | Aberdeen | 2000 |
| Rome Resources PLC | London | 1991 |
| Roneval Quarries Limited | | 1982 |
| Roose & Walney Sand & Gravel Company Limited(The) | Cumbria | 1960 |
| Roota Engineering Limited | Rotherham | 1973 |
| Rope Access Services Ayrshire Ltd | Irvine | 2022 |
| Ropeman Ltd | London | 2018 |
| Roperig Engineering Ltd | Peterhead | 2020 |
| Roping Limited | Dundee | 2015 |