Below is a list of runners who have reached 100 marathons in 2012 along with the event and date this milestone was reached.
| Betty Chan | 09-Dec-12 | Malaga Marathon |
| Karl Hinett | 04-Nov-12 | Pembrokeshire Coastal Challenge |
| Sally Ingledew | 29-Oct-12 | Dublin Marathon |
| Seamus Brennan | 29-Oct-12 | Dublin Marathon |
| Stuart Wild | 27-Oct-12 | Snowdonia Marathon |
| David Cremins | 14-Oct-12 | Liverpool Marathon |
| Dave Walsh | 14-Oct-12 | Leicester Marathon |
| Ian Scott | 16-Sep-12 | Green Chain Trm |
| Martin Wisdom | 16-Sep-12 | Green Chain TrM |
| Vanessa Brewster | 02-Sep-12 | Kent Coastal Marathon |
| Helen James | 26-Aug-12 | Boston 6hrs |
| Cat Marriott | 26-Aug-12 | Enigma Gold TrM |
| Conor Flanagan | 11-Aug-12 | Connemara 100 miles |
| Jon Errington | 25-Jul-12 | Enigma Night Fever TrM |
| Simon Redfern | 25-Jul-12 | Enigma Night Fever TrM |
| Rik Vercoe | 07-Jul-12 | Enigma Summer |
| Noel Jones | 24-Jun-12 | Herts Hobble ORM |
| Rosemary Nixon | 24-Jun-12 | Lancaster Marathon |
| Hugh Martin | 09-Jun-12 | South Downs Trail Marathon |
| Hideo Takano | 03-Jun-12 | Comrades Marathon (South Africa) |
| Jim Fletcher | 20-May-12 | Windermere Marathon |
| David Hall | 20-May-12 | Imerys Clay County TrM |
| Rita Williams | 13-May-12 | Halstead Marathon |
| John McCann | 07-May-12 | Belfast Marathon |
| Peter Dennett | 06-May-12 | North Dorset Village Marathon |
| Arthur Zammit | 06-May-12 | North Dorset Village Marathon |
| Lesley Yearley | 29-Apr-12 | Milton Keynes Marathon |
| Mike Kestle | 22-Apr-12 | London Marathon |
| Duane Daugherty | 15-Apr-12 | Bungay Black Dog Marathon |
| Matthew David | 14-Apr-12 | Caythorpe Canter TrM |