Ms Dalziel received 44,811 votes with nearest rival Darryll Park getting 28,260 votes.
She will lead city councillors: Sam MacDonald, Melanie Coker, Catherine Chu, Phil Mauger, James Daniels, Jake McLellan, Andrew Turner, Tim Scandrett, James Gough, Anne Galloway, Aaron Keown, Sarah Templeton, Jimmy Chen, Pauline Cotter, Yani Johanson and Mike Davidson.
She also attracted criticism when it was revealed her husband Rob Davidson's law firm representing China-owned water bottler Cloud Ocean Water.
Ms Dalziel said, with her husband at her side at a press conference, that she had been at a funeral and did not get the results until after they had been released.
"I'm really grateful, I know it is a big responsibility to take on a third term," she said.
With six new city councillors around the table she said she was "confident with the mix".
"We are really going to get our heads down," she said.
"I'm going to reach out to all the councillors and invite them to their first meeting tomorrow."
On Mr Swiggs losing his seat Ms Dalziel said: "I think that was inevitable with the number of things that had happened over the past few weeks."
"I have run an honest race and I guess the good thing is that I have made it competitive. I will be out there keeping things honest because I have learnt so much in the past eight weeks."
Mr Park did not rule out a return to politics.
Ms Dalziel now faces the challenge of ensuring the city's water supply remains chlorine-free following strict new rules around drinking water quality from the Government following the 2016 Havelock North contamination that left 5000 people ill.
She will lead the city through the next stage of its recovery from the 2010 and 2011 earthquakes — a job she is well familiar with.
Ms Dalziel won the mayoralty in 2013 after Sir Bob Parker said he did not believe he had "the energy to lead this city for another term" after leading the traumatised city through the aftermath of the 2011 earthquakes.
At the time, Ms Dalziel was serving as a Labour MP for Christchurch East. She resigned from her 23 years in Government before her bid from the mayoralty.
She was faced with a looming financial crisis, with the city's insurance yet to be settled. The terms of the cost-sharing agreement with the government, over who would pay what for the rebuild of the city's assets, had been shrouded in secrecy.
“We did not know what the terms of the cost-sharing agreement were until after the new council was elected," she previously told The Star.
A Dalziel-led council has completed major projects such as the city's new central library, Turanga, the Christchurch Town Hall and the James Hay theatre over the last term.
In 2016 she beat John Minto by 62, 407 votes and in 2013 Paul Lonsdale by 49,745.
