Passengers aboard were transported by tenders to the secluded island – home to a luxury resort and a research station - for a day trip with the option of hiking or snorkelling.
Suzanne Rees' daughter, Katherine Rees, said last week that her family was "shocked and saddened that the Coral Adventurer left Lizard Island after an organised excursion without my mum".
She described her mother, who was from Sydney, as an "active 80-year-old" who was a member of a bushwalking group.
"From the little we have been told, it seems that there was a failure of care and common sense."
Ms Rees added that she hoped the coroner's inquiry would be able to pinpoint what "the company should have done that might have saved mum's life".
"We understand from the police that it was a very hot day, and mum fell ill on the hill climb," she said.
"She was asked to head down, unescorted. Then the ship left, apparently without doing a passenger count.
"At some stage in that sequence, or shortly after, mum died, alone."
A search and rescue effort late on Saturday 25 October – the day she went missing – did not find any sign of Ms Rees. Her body was discovered the following day.
Last week Mark Fifield, the chief executive of the cruise operator Coral Expeditions, confirmed the firm was "working closely with Queensland Police and other authorities to support their investigation".
Mr Fifield said that the company was "deeply sorry that this has occurred" and had offered its full support to the Rees family.