The boy was born on the floor of the bathroom of their house around 6 pm, after “he arrived very quickly”.
“Run to the gym, take a rug, go to the bathroom, take the rug on the floor, towels down, braces, braces, braces,” Tindall said.
The baby, named Philip Philip, weighed 8 lbs 4 oz at birth, a spokesman for the couple told CNN.
The couple’s other two children, Mia Grace and Lena Elizabeth, were not home on Sunday for the new arrival, but they have seen him since then and are “over the moon,” said Mike Tindall.
The midwife, who had to meet them at the hospital, was quickly on the spot because she was not far away and a second came “when her head arrived”, he added.
Zara feels healthy, he said, and went for a walk with the baby.
“He was a warrior, as always, I always am,” Tindall said. “We can never judge a woman by what she has to go through at birth.”
He said there are advantages to giving birth at home. After Lucas arrived, Tindall watched an old game of rugby and a few bays with his new son.
Zara Tindall is a perfect equestrian who won a silver medal at a team event at the 2012 London Olympics.
She met her future husband during the 2003 Rugby World Cup, when he was playing for England. The couple married in Edinburgh in 2011.
CNN’s Amy Cassidy contributed to this report.