Emergency services were called to Beccles Lido yesterday after reports that a 15-year-old boy was unconscious in the pool.
Police were called by the ambulance service to the pool in Puddingmoor just before 6.40pm.
Paramedics treated the boy at the scene before he was taken to the Norfolk and Norwich University Hospital by air ambulance where his condition was described as serious.
He has now been transferred to Addenbrooke's Hospital where his is described as being in a critical but stable condition.
A police spokesman said: 'At this stage there do not appear to be any suspicious circumstances surrounding the incident.'
Shaun Crowley, chief executive of the lido, said: 'There was an incident at the lido yesterday where a boy had to be rescued from the pool by the lifeguards and resuscitated. The emergency services had to be called and he was airlifted to hospital.
'The lifeguards acted very quickly and started the resuscitation.
'He is now in hospital getting the best care and our thoughts are with his family.'
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