Her grandfather Fernando Riquelme, who often cared for his granddaughters, offered to run a warm bath for the girls.
He watched them in the bathroom before entering an adjoining bedroom for three minutes.
During that time the older sister pulled the plug and drained the bath.
Mr Riquelme refilled the bath and left Leila sitting in the water while he dressed her sister.
He told police he was out of the bathroom for a minute and did not hear any noise.
When he went back in, Leila was lying on her side in the bath with her nose and mouth under the water.
He picked up the child, splashing cold water on her in a desperate bid to revive her.
He then placed her on a bed and checked for a pulse before raising the alarm with the hotel's reception.
CPR was performed on the tot for about 20 minutes but she could not be resuscitated.
A post-mortem examination deemed Leila's "sad death" was due to drowning.
There was an indication the little girl had a viral infection but no evidence to suggest this had caused her death.
Detective Sergeant Mark Scott said the grandfather's actions leaving the little girl alone for a minute had shown "an unsuccessful degree of caution and care towards the deceased".
The court was satisfied there was no criminal liability or suspicious circumstances.
