The search for Lily Hooper, an 18-year-old who vanished five days ago during a hike in the NSW Southern Highlands, is entering a critical phase. Authorities are nearing a point where they may need to transition from a search for a survivor to a recovery operation.

Hooper was last seen leaving her parents' home in Oakdale, southwest of Sydney, at approximately 8 a.m. on Wednesday. She informed others of her intention to hike but has not been heard from since. Her father, Jim Hooper, expressed his distress, stating it had been "too long" since he had seen his daughter and urged the public to "throw love and energy" into the search.

The multi-day search effort involves NSW Police, NSW State Emergency Service (SES), and the Lifesaver 21 rescue helicopter. Police have indicated they are investigating all aspects of Hooper's life, including the possibility of foul play. Former homicide detective Charlie Bezzina told the Daily Mail that investigators will continue until they are convinced all avenues have been exhausted, at which point the operation would shift to recovery.

Bezzina highlighted the challenges of searching in rugged bushland, noting that difficult terrain and the presence of wildlife can hinder efforts to locate evidence. He also mentioned that survival experts are advising on the likelihood of survivability without food or water.

Authorities believe Hooper was hiking the Bonnum Pic trail in Nattai National Park. This 16-kilometer route is described as strenuous, involving extensive rock scrambling and difficult route finding. Trail guides warn hikers to proceed with caution and note that mobile phone signal is weak and unreliable. Hikers have previously advised downloading maps and not undertaking the trail solo due to its challenging nature and the potential to go off track.

Lily Hooper, who turned 18 in December, is a recent graduate of Campbelltown Performing Arts High School. Her martial arts group, Bujutsu Martial Arts and Fitness Centre, expressed devastation at her disappearance, noting that Hooper, who trained in Muay Thai, Brazilian Jiu-Jitsu, and MMA, was expected at a training session on Wednesday night.

Hooper is described as being of Caucasian appearance, approximately 175cm tall, with a slim build, long blonde hair, and blue eyes. She was last seen wearing a shirt and shorts. Police are seeking information from anyone who was on the Bonnum Pic walking trail on Wednesday or who may have any details regarding Hooper's whereabouts. Those with information are encouraged to contact Southern Highlands Police Station or Crime Stoppers.