| Name | Company Number | Date Appointed | Rating |
|---|---|---|---|
| Buoywork (Anglesey) Ltd | 01148912 | 31/12/1990 | Dissolved |
| HOLYHEAD TRANSPORTATION COMPANY LIMITED | 04682934 | 25/04/2003 | Dissolved |
| Holyhead Shipping Agency Ltd | 00789913 | 10/03/1992 | Dissolved |
| MAINSTAY MARINE SOLUTIONS LIMITED | 08938325 | 21/05/2014 | Silver |
| Penrhos Plant Hire Ltd | 01499563 | 30/11/1992 | Dissolved |
| TURBINE BOAT CHARTERS LIMITED | 07166793 | 01/03/2010 | Dissolved |
| Name | Company Number | Date Appointed | Date Resigned | Rating |
|---|---|---|---|---|
| Britannia Marine Towing Equipment Ltd | 02914025 | 06/04/1994 | 31/05/2001 | Dissolved |
| HOLYHEAD BOATYARD LIMITED | 00724907 | 10/03/1992 | 25/10/2024 | Gold |
| HOLYHEAD MARINE SERVICES LIMITED | 00895484 | 10/03/1992 | 25/10/2024 | Gold |
| HOLYHEAD TOWING COMPANY LIMITED | 00871758 | 12/12/1991 | 25/10/2024 | Gold |
| TURBINE TRANSFERS LIMITED | 06810857 | 05/01/2010 | 25/10/2024 | Not Trading |