Fatim Faye was walking to a bus stop in Grove Green Road, Leytonstone, when she started having contractions and panicked on December 11.
She was spotted by Sajjad Shariff, the driver of a W15 bus, who pulled over to help.
He called for an ambulance but after waiting for an hour, Miss Faye’s waters broke on the bus and Mr Sharriff decided to take her to hospital himself.
The 44-year-old gave birth to a healthy girl named Rakhy Giene Deme the next day at Whipps Cross University Hospital.
Now after returning home, she has paid tribute to the Mr Sharriff and Bee Cole, 27, who was the only passenger on the bus and stayed to help.
Ms Faye, who has three other children, said: “I have experience with difficult births where I’m unable to move. I knew the baby was coming.
“I thank everyone, the bus driver and Miss Cole for helping me, for saving me.”
Ms. Faye’s husband, Ndiogou Deme, rushed across London from his job as a restaurant chef in the Strand to join his wife on the bus after being called by Mr Sharriff.
“I was surprised to find them there, still waiting for an ambulance,” he said.
“I have to thank everyone at the station, especially the bus driver, Miss Cole and the hospital because the delivery was quick and easy. I have to thank everyone. God bless everyone.”
Ambulance controllers later claimed that they were mistakenly told that Miss Faye was nine weeks pregnant instead of nine months, so failed to register the call as urgent.