Commander Jane Allen, 60, was 4,300 miles in to her challenge when she fell near Milford Haven, Pembrokeshire.
She was left with a chipped bone in her arm and dislocated shoulder - an experience so painful she was placed under general anaesthetic during treatment at Haverfordwest hospital.
She said: 'Walking my waterside route, it struck me as odd that the Pembrokeshire oil refinery is such a feature in Pembrokeshire's National Park.
'The next thing to strike me was a small rock hidden in the grass - in a split second I tripped and was thrown downhill where I lay screaming with pain.'
Jane, who was a 2012 Olympic Torchbearer, has spent the last four weeks in Haverfordwest recovering from the accident.
Speaking to the Western Telegraph, she said: ‘Everyone we’ve met in the area has been incredibly helpful and friendly.
‘I know we’ll be sad to leave this corner of Pembrokeshire.’
Jane began her journey at HMS Victory on Trafalgar Day, Saturday October 21, 2017.
Her inspirational effort has raised more than £14,000 for the Royal Navy and Royal Marines Charity (RNRMC) and Women’s Royal Naval Service Benevolent Trust (WRNS BT)
The director of fundraising and marketing for the RNRMC, Alasdair Akass, said: ‘Jane has demonstrated tremendous spirit, grit, and determination to be able to re-start her tough challenge.
‘We are so grateful to Jane for raising vital funds for the Royal Navy and Royal Marines Charity.’
The RNRMC distributes millions of pounds annually to military charities which care for the children, families and veterans of the Royal Navy and Royal Marines.
Jane resumed her walk todayMON, and hopes to arrive back in Portsmouth in the autumn.
To donate, go to: Virginmoneygiving.com/victorywalk17-18