| Rosava Capital Holding Ltd | Sheffield | 2025 |
| Roscot Ltd | Montrose | 2007 |
| Rose Petroleum (UK) Limited | London | 2013 |
| Roseberry Offshore Services Ltd | Stockton-On-Tees | 2023 |
| Rosehaugh Energy Limited | Fraserburgh | 2023 |
| Rosetti Marino UK Limited | Aberdeen | 2013 |
| Roskena Ltd | Edinburgh | 2013 |
| Ross Drilling Consultants Ltd. | Dundee | 2001 |
| Ross Quality Services Limited | Aberdeenshire | 1996 |
| Ross Quarry Products Limited | Dundonald | 2022 |
| Ross Rigs Ltd | Wirral | 2022 |
| Ross Training Consultancy and Associates Ltd | Brechin | 2024 |
| Ross Well Services Ltd | Montrose | 2023 |
| Rosslyn Audio Limited | Aberdeen | 2013 |
| Rosslyn Projects Limited | Dundee | 2024 |
| Rotating Machinery Works Ltd | Sunbury-On-Thames | 2023 |
| Rotech Subsea Limited | Aberdeen | 2013 |
| Rotech Systems Limited | Dagenham | 2018 |
| Rotherham Sand and Gravel Company Limited(The) | Doncaster | 1930 |
| Rotideb Company Limited | Manchester | 2024 |
| Roulston Plant Services Ltd | Doncaster | 2019 |
| Rovagold Limited | Kingston-Upon-Thames | 1997 |
| Rovbod Services Limited | King'S Lynn | 2009 |
| Rovin Consultants Limited | Stockton-On-Tees | 2008 |
| Rovivor Ltd. | Isle Of Lewis | 2017 |
| Roxane Minerals Limited | St. Ives | 2012 |
| ROY DO Limited | London | 2011 |
| Royex Ireland Ltd | Newry | 2017 |
| RP Electrical Solutions Limited | Dundee | 2014 |
| RP Hydro Survey Consultants Ltd | Merthyr Tydfil | 2020 |
| RPG Maintenance & Inspections Ltd | Houghton Le Spring | 2025 |
| RPM Management Holdings Ltd | Sheffield | 2022 |
| RPW Contracts Limited | Glasgow | 2026 |
| RR Minerals Limited | London | 2017 |
| RRC Completions Ltd | Montrose | 2019 |
| RRR Coal Ltd | London | 2019 |
| RS Monitoring Solutions Ltd | Stonehaven | 2025 |
| RS Petroleum Engineering Ltd | Montrose | 2005 |
| RSA NI Ltd | Newtownabbey | 2026 |
| RSH Inspections Ltd | Wakefield | 2025 |
| RSL NE Limited | Newcastle Upon Tyne | 2016 |
| RSM Scotland Limited | Aberdeen | 2019 |
| RSS Engineering Solutions Limited | Great Yarmouth | 2015 |
| Rss-Recycling & Screening Supplies Ltd | Ellesmere Port | 2023 |
| RST Global Solutions Holdings Limited | Rickmansworth | 2015 |
| RT Commercial Energy Consultants Limited | Steyning | 2016 |
| RT Mining Ltd | London | 2024 |
| RTC Plant Hire Limited | Camelford | 2008 |
| Rtmining Consulting Ltd | Caterham | 2021 |
| RTR Solutions Limited | Aberdeenshire | 2005 |
| Rubicon Integrated Services Ltd | Warminster | 2014 |
| Rubin Diamond&Gold Ltd | Cardiff | 2025 |
| Rubislaw Associates Ltd | Aberdeen | 2012 |
| Ruby Geoconsult Ltd | Wymondham | 2008 |
| Rubylous Limited | London | 2018 |
| Rubymark Limited | Gainsborough | 2018 |
| Runswick Drilling Limited | Whitby | 2024 |
| Rupert Resources Management Solutions Ltd | Hitchin | 2025 |
| RUS Akeniva Ecological Science Ltd | Cambridge | 2025 |
| RUS Lamif International Fertilizer Co., Ltd | Cambridge | 2025 |
| RUS Maimat Energy Huagong Group Co., Ltd | Cambridge | 2024 |
| RUS Protia Mining Group Co., Ltd | Cambridge | 2024 |
| RUS Wulaer Huagong Group Co., Ltd | Cambridge | 2024 |
| Ruseman Offshore Ltd | Norwich | 2013 |
| Rusenergy Business Development (UK) Limited | London | 2009 |
| Rushmoor Services Ltd | Retford | 2019 |
| Russell Bell OFF Shore Services Ltd | Bungay | 2026 |
| Russell CT Limited | Inverurie | 2026 |
| Russell Mineral Equipment (UK) Ltd | London | 2013 |
| Russia Sural Sylvite Ltd | Cambridge | 2023 |
| Ruune Logistics Limited | Great Yarmouth | 2023 |
| RWC Electrical Services Ltd | Blackpool | 2019 |
| RWD Milcam Limited | Fraserburgh | 2013 |
| Ryan Offshore International Ltd | Falkirk | 2023 |
| Ryan Ward Services Ltd | Perth | 2016 |
| Ryedale Aggregates Limited | York | 2010 |
| Ryline Well Intervention Ltd | Eskbank | 2023 |
| Ryocca Limited | Cardiff | 2023 |
| Rysco Corrosion UK Limited | Aberdeen | 2022 |
| Rzrropeaccess Ltd. | London | 2025 |
| S & S Landscaping Contractors Limited | St. Ives | 2021 |
| S a Fairgrieve Limited | Macmerry | 2009 |
| S D S Services Ltd | Great Yarmouth | 2008 |
| S D Service Solutions Ltd | Ashington | 2016 |
| S Donaghy Production & Operation Services Limited | Middlesbrough | 2018 |
| S G Curry Limited | Co Armagh | 2001 |
| S H U E Limited | | 2004 |
| S Hill Bolting Solutions Ltd | Newbiggin-By-The-Sea | 2021 |
| S Hood Services Ltd | Great Yarmouth | 2026 |
| S I a NDT & Inspections Ltd | Waterlooville | 2022 |
| S Lift Ltd | London | 2025 |
| S Mcconnell & Sons Ltd | Belfast | 2003 |
| S P Measurement Consultancy Services Ltd | Great Yarmouth | 2025 |
| S P W ALL Access Limited | Lancaster | 2017 |
| S Scott Ltd | Forfar | 2007 |
| S&E Insulation Ltd | Medway | 2026 |
| S&N Interventions Limited | Norwich | 2018 |
| S&R Offshore Solutions Ltd | Beccles | 2018 |
| S-Paris Capital Limited | London | 2014 |
| S.A.J.D Limited | Whitby | 2013 |