Maya Kantengule was found at the bottom of a swimming pool at Waveney River Centre holiday park in Burgh St Peter, Norfolk, on May 1 2016.
She was declared dead later that day at James Paget University Hospital.
South Norfolk Council environmental health officer Chris Coker said people swam at the centre at their own risk.
Maya's father, Livial Kantengule, said in a written statement at the inquest in Norwich that he spoke to Jane Rainer, the mother of his daughter's best friend, as he arrived and decided not to wait at the pool during the party.
He returned there with his wife, Glenda, after receiving a message there had been an accident.
Maya had already been taken to the hospital near Great Yarmouth. Her parents were at her bedside when she was pronounced dead.
Mr Kantengule said he did not ask if there was a lifeguard.
"Jane used to volunteer to help with the swimming lessons, so we assumed Maya would be adequately supervised while in the pool," he said.
Maya, from Smith's Walk, Oulton Broad, near Lowestoft, Suffolk, attended Dell Primary School.
Jaqueline Bell, a teaching assistant at the school, said in a written statement that Maya started weekly swimming lessons in reception year.
"She was nervous in the water and would use armbands and a woggle," she said.
Mr Coker told the inquest the indoor pool at Waveney River Centre could be privately hired.
He said it was 1.5m (5ft) at its deepest and signs were up stating there were no lifeguards on duty and that people swam at their own risk.
The inquest, expected to last two days, continues.

The group are due to be brought to a hostel in the countryside near Great Torrington, Devon on Sunday or Monday.
The children will be transported from Croydon, south London, where they were taken from the Jungle camp by a private security company.
The Home Office said they are unaccompanied, vulnerable children.
It is not clear if the children are among a group that arrived under the "Dubs amendment" which grants refuge to particularly vulnerable individuals, such as those who are unaccompanied and without family ties in the UK.
The purpose of the temporary facility is to provide a safe and welcoming place before the children are reunited with family members or moved to other parts of the country, Devon Country Council said.
The council said it is working with the police, NHS and other local authorities as part of the "emergency response".
"These will be vulnerable young people," Councillor James McInnes said. "They will be frightened and they will be exhausted, and we as an authority have a statutory responsibility to support those that present in Devon."
Dozens of private security guards will accompany the group. A source told the BBC most of those expected in Devon are over 16 years old.
Geoffrey Cox, Conservative MP for Torridge and West Devon, said the move will not be a "permanent institution".
"The majority of the children will only be here for a few days," he said.
"They will be under 18 and there is no question of anyone over 18 coming."
The Home Office declined to comment on the details of the transfer, but added the children were often traumatised and their privacy should be respected as they received support to rebuild their lives.
A seven-year-old girl drowned at her best friend's birthday pool party while there was no lifeguard on duty, an inquest heard.
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Up to 70 child migrants from the Jungle camp in Calais are expected to arrive at a temporary Home Office "respite facility", the BBC has learnt.