John Kosmina has resigned as coach of Adelaide United, ending days of speculation that he would be sacked.

In a brief statement to the media in Adelaide, Kosmina said his three-year journey with the club had to end.

United have been widely criticised for their behaviour during and after its 6-0 loss to Melbourne Victory in the A-League grand final on Sunday.

Kosmina, who had another year remaining on his contract, said the past few weeks at the club had been a harrowing experience.

He maintained that he was not pushed but said he made the decision for the benefit of his team and family.

"I was born and bred in Adelaide and after a long, long time away I threw a pebble in the pond by coming back," he said.

"The final wave of those ripples are just hitting the shores now and my journey here has come to an end."

Assistant coach Aurelio Vidmar will replace Kosmina as the interim coach until next year.

United captain Ross Aloisi has been replaced by Angelo Costanzo.

Kosmina said he tendered his resignation to United's board "after a lot of thought and soul-searching".

"It is a decision I have made in the best interests of my family and, as importantly, the team," he said.

"I have had three wonderful seasons with the club watching it grow and having a lot of fun along the way.

"We have achieved so much in a very short space of time and for that I am very proud.

"However, there have been times when my actions have got me into trouble and caused grief for a number of people, myself included, and I apologise for that."

Kosmina thanked the people of South Australia for their support, saying that he had learnt much and had developed as a person.

"For me a big part of my life is about learning from your mistakes and I have learnt a lot from mine," he said.

"In the next few weeks, I need to spend some time with my family with my wife and best friend Aly, who has been a wonderful support to me over the past 18 years.

"I have five children who need me to invest a lot more emotional energy in them.

"In conclusion, I wish the club and the players every success in the future."

Kosmina did not field questions after his statement, promptly shaking hands with club owner Nick Bianco and chief executive Michael Petrillo before leaving the press conference.

Brought to you by AAP © 2024 AAP