Police were alerted to reports of a fight at 4.35pm on the bank holiday Good Friday in Goldcrest Way, New Addington.
Three males – aged 15, 16 and 18 – were rushed to hospital after sustaining stab wounds.
London Ambulance Service and the police had attended the scene in Goldcrest Way.
The conditions of the injured teenagers have now been assessed as non-threatening.
Two of the three teenagers have now been arrested on suspicion of affray.
All three remain in hospital at this time.