Speaking in the aftermath of England's 4-0 Ashes defeat, Bayliss said that he had made clear to Andrew Strauss, the director of England cricket, a year ago that he would not be seeking an extension regardless of results.
It means that Bayliss, who was appointed in 2015, will leave the role following a season that will include England's tilt at the home World Cup and the next Ashes series.
"I told Andrew Strauss probably 12 months ago that September 2019 I'm contracted to and that would see me out," Bayliss said. "I've never been anywhere any more than four or five years. Whether you're going well or not I've always felt that round about that four-year mark is time to change. A new voice, a slightly different approach slightly reinvigorates things. So I passed that on him 12 months ago."
England's comprehensive Ashes defeat has continued a poor run of form away from home in Tests since beating South Africa on the 2015-16 tour. They drew 1-1 in Bangladesh, lost 4-0 to India and were flirting with another Ashes whitewash before the draw at Melbourne.
However, Bayliss has overseen a dramatic improvement in England's limited-overs cricket - they have reached the final of the World T20 and semi-final of the Champions Trophy under his watch - and he has been given the support of the ECB hierarchy during this Ashes tour so he remains safe in his job.
Bayliss also hinted that he could see Joe Root still being captain for the next Ashes in Australia in 2021-22. It is very rare for an England captain to get two chances to lead in Australia - it has not happened since Johnny Douglas in 1911 and 1920, either side of the first World War.
"I think someone coming for the first time as captain, even with experience, it's going to be a hard tour to be on," Bayliss said. "I think he handled it pretty well. He is a young captain and I would expect in four years, when he comes back with another four years experience and an away Ashes under his belt, he'll feel a lot more comfortable."
England's next Test assignment is two matches in New Zealand at the end of March for which the squad is due to be named on Wednesday morning in Australia although the final selection meeting has been delayed due to Root's illness on the final day in Sydney.
James Vince and Mark Stoneman are under pressure after mediocre Ashes returns. Gary Ballance, who has been the spare batsman in Australia is expected to miss out, while Moeen Ali also had a torrid series. In spite of that, Bayliss did not foresee major changes.
"I can't see too many big changes. We've known for a couple of years we've been three or four performing players short of a very, very good team. We've had good performances at home in Test cricket but a lot of that's been on the back of our big five or six players.
"Trying to fill those last three of four spots so you've got that consistency in the team would help away from home. Malan has probably done enough, he's probably cemented one of those spots we were after.
"James Vince and Mark Stoneman have shown what they're capable of but would be a little disappointed they weren't able to capitalise on some of their good play.
"If guys like that can capitalise on their starts and make big hundreds that gives us across out top seven players who are performing well."