The organisation of a rugby trip to France during which a teenage boy drowned in a lake was "inadequate" and "slipshod," an inquest has heard.
Harry Sykes, 16, from Bradford, was on a trip with the Halifax Elite Rugby Academy when he died while swimming in a lake near Carcassonne in 2018.
An inquest at Bradford Coroner's Court heard he was not reported missing until his team got back to their hotel.
He was found in 6ft 6in (2m) of water, 66ft (20m) away from the beach.
Recording a narrative conclusion, West Yorkshire senior coroner Martin Fleming said there were "significant flaws" in the organisation and preparation of the visit to the lake.
"This resulted in confusion and uncertainty with respect to supervision, which was at best, sporadic," he said.
"The lack of head counts... enabled Harry to disappear," he added.
Mr Fleming said that nobody had noticed Harry was not in a group photo taken before they left the lake, and that a "cursory" check of the beach had failed to alert them to the fact that Harry's bag and towel were still there.
The inquest previously heard the teenager was last seen alive in the water at Lake Cavayere at 13:30 on 5 September 2018, but he was not reported missing until about 18:00.
The French authorities were contacted and divers were later dispatched, recovering Harry's body from the lake that evening.
Mr Fleming said brothers Lee and Gareth Greenwood, both former professional rugby players who founded Halifax Elite Rugby Academy, were in breach of their duties.
He said failings included "taking insufficient supervisors to the lake, failing to supervise boys properly at times, failing to designate a supervisor when leaving the beach and failing to conduct head counts while on the beach".
But he said these did not give rise to a serious risk of death and did not amount to gross negligence manslaughter.
"There is no evidence he [Harry] was at particular risk of drowning, no evidence he was in distress or called out for help."
Mr Fleming told the court the teenager had suffered a cardiac event of uncertain origins while swimming and drowned in unclear circumstances when he was not observed to be in difficulties.
"It remains unclear whether if he had been seen and retrieved, it would have made any difference to the outcome."
Following the inquest, Harry's mother, Natasha Burton, said: "We are astounded that yet again justice has not been served for Harry.
"This was a tragic and unnecessary death. The coroner himself has said the organisation and preparation of this trip was inadequate and slipshod, with only sporadic supervision.
"There needs to be more failsafe procedures put in place for all students 16 to 18 years old regardless of their specialist activities," she said.
"Harry continues to be missed by all his family. This is felt every day," she added.