Damien Little and his sons Koda and Hunter were "three lives taken from this world too soon", their family says amid a funeral service in Port Lincoln.
Loved ones and friends gathered at the Unity Hill Christian Ministry Centre on Wednesday more than two weeks after Mr Little, 34, shot himself and his children before driving off the Eyre Peninsula town's main wharf.
"We will share sadness that we can no longer see their smiles, enjoy their hugs and watch them grow," a family statement released during the service said.
"We will also celebrate the special times and the joy they brought us.
"Damien, Koda and Hunter blessed so many with their presence and today is the start of the next journey without them.
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Wife Melissa also wrote emotional poems for her sons and husband which were printed on a card for the service.
"A baby so sweet with a precious smile. The time I had with you was so worthwhile," her tribute for nine-month-old Hunter read.
To four-year-old Koda, she wrote: "You should have had so many years to watch your life unfold."
Mrs Little said her husband had left a hole in her heart that could never be filled.
"If love alone could have saved you, you never would have died," she said.
In the wake of the tragedy, Mr Little's family revealed he had suffered with mental health issues for the past three years.
Port Lincoln Mayor Bruce Green described the funeral as another tough day for the community which was still struggling to come to terms with the tragedy.
"There's really deep sorrow and sadness and people are unable to rationalise what happened and find it really difficult to know what to do next apart from getting on with their lives," he told AAP.
The deaths prompted locals to line the wharf with flowers, teddy bears and other tributes.
An appeal was also launched to help Mr Little's wife with ongoing expenses and has raised more than $63,000 so far.
* For support and information about suicide prevention, call Lifeline on 13 11 14
