The appointment was announced on March 4.
Mr Rice (47) will become the youngest bishop in the country when he is ordained at St John's Cathedral, Napier, on June 7.
"With many of the present bishops at retirement age it is time for the next generation,'' he said.
The speed of the ordination was so the bishop-elect would be installed in time to attend the Lambeth Conference in Canterbury, England, in July.
Mr Rice, who was farewelled by the city at a civic reception earlier this week, said it would be sad to say goodbye to the city he and his family had called home since January 2002.
"The reality has finally sunk in that we are leaving, and we have been reflecting on the past six years.''
During his tenure as the Dean of Dunedin, the cathedral had become a more welcoming place and was ready to build on its strong support.
"When I arrived, there was little going on and there had been some difficult years for the cathedral, but I am confident the positive direction in recent years will continue.''
Mr Rice, who is a keen fly fisherman, said while he would miss Otago rivers, he was looking forward to exploring the area of Waiapu, which includes the Hawkes Bay and Bay of Plenty.
"I have spent many enjoyable Mondays fishing with my buddies, and I will miss that.''
With his son Ian (15) expressing an interest in attending the University of Otago in the future, Mr Rice said he and his family would return to Dunedin as often as possible.
"It has been my pleasure and my honour to be based here and I am indebted to the people of this cathedral, city and diocese for their assistance in making this opportunity happen.''
Until a replacement dean is finalised, the Very Rev Gavin Yates, of Christchurch, will be working at the cathedral.
