Six months ago, Walter had signed on with Otago for another two years and was set to stay with the Volts until 2023.
But he has now taken up the job as head coach of the Central Districts Stags and will start with his new team next month, based in Napier.
Walter said he was not at all looking to leave Otago, after five years with the side.
"I was happy with Otago and had no issues. But one thing I have learnt about coaching is that every opportunity which comes along you have to consider it," he said.
"It was certainly not something I was thinking about. But the opportunity came up and it is the right time for me to move on."
Walter (45) said when he saw the Central Districts job advertised that was the first time he had even thought about changing jobs.
The move had nothing to do with any dissatisfaction with Otago.
"We are really starting to make strides and that was another reason it was such a tough decision to move on."
Walter said there was no one factor which had been the basis of his departure.
The process had taken a long time, with many sleepless nights, and a lot of conversations with different people.
The South African said he was grateful to Otago for taking a chance on him five years ago.
"There are a massive amount of highlights.
"There have been some tough times but they are far outweighed by the good times — just the emergence of some players who have made New Zealand A sides and then into the Black Caps.
"I have seen the team grow, made back-to-back Ford Trophy finals."
He pointed to a seven-wicket bag in a one-day game by Michael Rae, a hat-trick by the same player and the Plunket Shield win over Central Districts as highlights of the season which had just ended.
In his five years with Otago the team did not win a trophy which Walter admitted was something no coach wanted.
"All coaches will always tell you how much they love to have something in the trophy cabinet. But I am far prouder of what we have achieved as players and a team."
Walter would join Central Districts, a side which has plenty of player resources but it did not win any competition last season as Canterbury dominated. He replaces Aldin Smith, who has moved into a performance and pathway coaching role, after two years as head coach of the Stags.
Walter’s wife, Heather, was the Otago Cricket Association’s head of events and sponsor relations so she will be departing too.
The couple have two boys, William, who is about to turn 5, and Matthew (3).
Otago Cricket Association
chief executive Mike Coggan expressed his gratitude for the contribution Walter had made to Otago’s professional environment.
“Rob has transformed the way our players think and prepare for cricket.
"We now have quality structures and processes in place and our new head coach will be able to seamlessly fit into our professional system," Coggan said.
A search for a new coach would start immediately as players train through winter. Heading overseas to play is not an option.
