Celine Cremer set off on a walk at Philosopher Falls in Tasmania's remote northwest on June 17, 2023, and was reported missing almost 10 days later.
Extensive initial police efforts found no trace of the 31-year-old, before private searches organised by her friends and family discovered her remains near a river in January 2026.
In findings published on Friday, coroner Madeleine Wilson ruled Ms Cremer died between June 17 and 21, 2023 as a result of an accident.
Her death followed a "confluence of errors" that began when she took a walking track towards Magnet Dam after visiting the Philosopher Falls lookout.
"The track to Magnet Dam was not well defined and she wandered off track and became lost," Ms Wilson said.
"The deviation from the track occurred late in the day, four days before the winter solstice, at which time the afternoon light was starting to fade."
Overnight temperatures in the area at the time were close to freezing and Ms Cremer had insufficient clothing, including nothing waterproof, Ms Wilson said.
Phone reception was intermittent and she lost her mobile, which was her only form of communication, late in the afternoon on the day she set out.
Her phone was found by a search party of volunteers in December 2025.
Recovered data showed she took several photos and videos between 2.21pm and 2.42pm and used Google maps several times afterwards with the last input recorded at 4.18pm.
It is likely Ms Cremer got lost around 3.49pm and subsequently became disorientated without her phone and mistakenly changed direction, the coroner said.
"It is not possible to determine the route taken once Ms Cremer lost her mobile phone, to her final resting place in the Arthur River," Ms Wilson said.
It was possible Ms Cremer slipped and fell, or tried unsuccessfully to cross the river.
Ms Cremer had travelled to Australia in 2022 on a working holiday and was planning to return to the mainland four days after the Philosopher Falls walk.
Ms Wilson praised the efforts of a private search company and volunteers which ultimately led to the first discovery of Ms Cremer's remains.
The police response to the missing person report was appropriate and their search efforts were guided by "accepted methodologies".
Police efforts were somewhat limited by weather, Ms Wilson said, noting water levels in the Arthur River were significantly higher in 2023 than when her remains were found.
Tasmania Police has committed to a review into the use of private search groups in missing persons investigations, including consideration of formal protocols.
Ms Cremer failed to follow standard safety precautions, such as taking appropriate equipment and telling people where you are going, Ms Wilson said.
"Walkers should familiarise themselves with these standard safety messages before embarking on short walks, day walks or multi-day hikes," she said.
"Walkers should also be aware that mobile coverage is often intermittent or unavailable in remote areas of the Tasmanian wilderness and should plan accordingly."
Ms Wilson recommended the local council put up signs at the entrance to the Philosopher Falls track, explaining it is not managed for recreational use and the surface is degraded, uneven and may be hazardous.
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