| Xplore App Limited | Information & communication | 2025 |
| Xtsp Ltd | Administrative & support | 2024 |
| Y Summer Limited | Hospitality | 2024 |
| Yacht Felicia Ltd | Transport & logistics | 2017 |
| Yadster Ltd | Real estate | 2023 |
| YAK YAK Games Limited | Information & communication | 2022 |
| Yalestone Ltd | Real estate | 2012 |
| Yalestyle Limited | Households | 1984 |
| Yangfan Consulting Management Limited | Real estate | 2024 |
| Yatesea Marine Ltd | Other services | 2024 |
| Yavas Estate Ltd | Real estate | 2024 |
| Yayyay Group Limited | Information & communication | 2013 |
| Yayyay Holdings Limited | Agriculture & fishing | 2022 |
| Yayyay Limited | Information & communication | 2013 |
| Yejanic Ltd | Transport & logistics | 2026 |
| YEJANIC101 Ltd | Transport & logistics | 2026 |
| Yeltech Ltd | Manufacturing | 2004 |
| Yesi Foui Ltd | Wholesale & retail | 2025 |
| Yippee KAY Nine MF Ltd | Wholesale & retail | 2023 |
| Yoke-Creative Wellbeing Ltd | Arts & recreation | 2025 |
| Yoni.London Ltd | Arts & recreation | 2015 |
| York House (Guildford) Management Limited | Households | 2004 |
| Yorkshire Three Peaks Challenge Ltd | Extraterritorial | 2021 |
| Yorkshire Three Peaks Ltd | Extraterritorial | 2021 |
| Yotbud Ltd | Information & communication | 2025 |
| Yougrow.Ai Limited | Information & communication | 2024 |
| Youness Cleaning Ltd | Other services | 2017 |
| Young Athletes Clubs Ltd | Arts & recreation | 2011 |
| Young Creators Movement Ltd | Education | 2026 |
| Your Big Day Music Ltd | Arts & recreation | 2015 |
| Your Cliff Edge Ltd | Professional & scientific | 2020 |
| Your Furniture Outlet Ltd. | Wholesale & retail | 2021 |
| Your Legal Limited | Professional & scientific | 2017 |
| Your Money Made Simple Limited | Financial services | 2007 |
| Your Physiology Limited | Health & social care | 2023 |
| Your Thinking Partner Limited | Professional & scientific | 2012 |
| Your World Travel Limited | Administrative & support | 2019 |
| Yourcleaner Ltd | Administrative & support | 2023 |
| YS Chen Limited | Hospitality | 2018 |
| Yt-Industries UK Ltd | Manufacturing | 2019 |
| Yuvan Homes Ltd | Real estate | 2021 |
| Yvonne Arnaud Theatre (Productions) Limited | Arts & recreation | 1985 |
| Yvonne Arnaud Theatre Trust | Arts & recreation | 2024 |
| Zagros Energy Limited | Mining & quarrying | 2011 |
| Zaitouna Express Ltd | Hospitality | 2023 |
| ZAP ZAP Vehicle Hire Limited | Administrative & support | 2022 |
| Zara RF Ltd | Manufacturing | 2025 |
| Zareen ALI Consulting Ltd | Professional & scientific | 2026 |
| Zasha Limited | Health & social care | 2016 |
| Zavl Limited | Wholesale & retail | 2025 |
| Zaxrad Ltd | Administrative & support | 2016 |
| Zenga D Limited | Information & communication | 2005 |
| Zenkki Ltd | Wholesale & retail | 2020 |
| Zenon Recruitment Limited | Administrative & support | 2006 |
| Zentrix Security Services Limited | Administrative & support | 2026 |
| Zenval Communities CIC | Education | 2025 |
| Zero 32 Limited | Information & communication | 2013 |
| Zerolatency UK Limited | Arts & recreation | 2024 |
| Zeus World Limited | Administrative & support | 2022 |
| ZH Pilates Studio Ltd | Arts & recreation | 2020 |
| Zigatron Ltd | Information & communication | 2020 |
| Ziggycroccy Ltd | Real estate | 2020 |
| Zion Energy Limited | Construction | 2023 |
| Zion Sport Global Limited | Arts & recreation | 2015 |
| ZIP I.T. Limited | Information & communication | 1997 |
| Zipa Property Management Limited | Real estate | 2022 |
| Ziron Limited | Information & communication | 2011 |
| ZIV Holding and Investments Limited | Real estate | 2005 |
| Zmc-Uk Co., Ltd. | Professional & scientific | 2019 |
| ZOE Gulliver Ltd | Health & social care | 2014 |
| Zola Engineers Limited | Manufacturing | 2010 |
| Zoltan Cleaning&Maintenance Ltd. | Administrative & support | 2020 |
| Zoltstar Consultancy Limited | Professional & scientific | 2017 |
| Zoneconcept Ltd. | Households | 1999 |
| Zonespot Residents Management Limited | Other services | 1986 |
| Zonexa Ltd | Wholesale & retail | 2025 |
| Zurito Limited | Information & communication | 2006 |
| Zutato Limited | Professional & scientific | 2016 |
| Zvprop Ltd | Real estate | 2017 |
| Zynora Ltd | Information & communication | 2024 |