The mishap occurred this morning near Jonnadha village of Alamuru mandal, when 11 members of the marriage party including the newly-wed couple were travelling from Bhimavaram in West Godavari district to Annavaram to visit a temple, they said.
When the car reached Jonnadha, the driver of the car lost control over it while negotiating a small turn. Following this, the car overturned and fell into the canal, Ramachandrapuram Deputy Superintendent of Police Muralikrishna said.
While Madhav Sri (6) was killed on the spot, Krishna (36) and Krishna Sri (4) later succumbed to their injuries in a hospital, an official attached with Alamuru police said.
The injured including the driver were admitted to nearby hospitals, the DSP said, adding investigations are underway.