Suraj Mall died after he was found floating face down in a leisure centre swimming pool in February 2008.
Wolverhampton Crown Court was told that lifeguard Kelly Woods, 31, wasn't paying attention to the swimmers and had failed to notice the child was drowning at Wolverhampton Swimming and Fitness Centre.
She went on trial on Monday charged with failing to properly supervise pool users.
Prosecutor Mr James Puzey said Woods had dived into the pool to try to save the schoolboy but by then the youngster had already been submerged face down in the pool for almost two minutes.
Despite attempts to revive him Suraj was later pronounced dead at New Cross Hospital. Mr Puzey said: "(Woods) was at work and got talking to a customer while she was on duty.
"A few minutes later a boy – Suraj Mall – was found floating face down in the water."
The youngster's mother, who had taken Suraj and his three siblings to the pool, broke down in the witness stand as she recounted the events of the day.
Lajla Kaur, 35, went for a brief induction at the centre's gym and returned to see her four children in the pool's shallow end through a glass window. She then went to get change for a locker and on returning couldn't see her son.
She said: "Suraj wasn't there and I kind of panicked. When I got the children's attention they couldn't hear me through the glass.
"When they did finally understand they pointed towards the changing room. "Then I heard the alarm and people were coming out of the pool."
Jurors also heard from five lifeguards who were on duty the day Suraj died.
Natalie Emery, 24, said rules dictated that conversations with customers of up to two minutes were not permissible.
Lifeguards took half-hour shifts overseeing one area of the centre and the most recent changeover had occurred at 4.30pm – 19 minutes before a 999 call was made about the drowning.
Miss Emery said: "I noticed Kelly was talking to a gentleman. It was for between 10 and 15 minutes."
But customer Barry King said he and Woods, from Tettenhall Wood, West Midlands., were talking for just 'a couple of minutes'. He said he went over to chat to Woods about a previous incident where he had been told the shorts he wore were too long to swim in.
He said: "She was concentrating on her job and I don't think I distracted her."
The trial continues.