The toddler was reportedly playing beside the apartment block pool when they slipped and fell into the deep end about 7pm on Sunday, sparking what would become a double Easter tragedy.
The child's father, 38, and grandfather, 65, leapt into the pool to try to save the toddler only to get into trouble themselves.
The Queensland Ambulance Service's Mitchell Ware said bystanders were able to pull the people from the pool and performed CPR until paramedics arrived, however, the grandfather and father died at the scene.
A woman known to the two men was taken to Gold Coast University Hospital in an emotional but stable condition.
"It's an extremely emotional scene. Anyone could understand that not just to lose one family member but to lose two family members," Mr Ware said.
"These incidents can have long-lasting effects for not just the family members involved, but also the people that were at the scene as well, and also the first responders."
Authorities have advised people who are not strong swimmers to exercise caution around any body of water.
The family was understood to be holidaying at the apartment complex on Orchid Avenue.
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