He will leave the airline in October, the company announced in a statement.
He had been with the company five years.
Foran said in a statement that leading Air New Zealand had been one of the "greatest privileges" of his career.
"I am humbled by the work Air New Zealanders do every day and their extraordinary commitment to each other, our customers and our country."
He said Air New Zealand had had to battle issues outside its control but had managed to continue and improve.
"I'll leave later this year knowing Air New Zealand's foundations are immensely strong."
Board chairperson Dame Therese Walsh said Foran had told members he believed it was a good time for him now to take up a new challenge.
She said he had told the board the airline was set up well for growth.
Foran had displayed "exceptional leadership", she said.
Dame Therese said Foran had had to guide Air New Zealand through "global aviation's most significant crisis" referring to Covid-19, which saw national boundaries closed and airlines having to stop flying routes.
"Perhaps his most notable contribution has been managing significant global supply chain challenges. These begun with Covid-19, and continue today with the engine issues materially impacting both our Boeing and Airbus fleets."
The Air New Zealand board will carry out a global search for a replacement.
In the months to his departure on October 20, Foran would work with a new chief executive to prepare for the role, Walsh said.
Air New Zealand, which has more than 11,000 employees, is the country's flag-bearing carrier.
The airline made the announcement to the NZX at 12pm today.
Just before Christmas, Foran told RNZ's Checkpoint that Air New Zealand would face issues for two to three years over maintenance issues with the Rolls Royce Trent 1000 engines on its 787 Dreamliners, following concerns of premature wear and weakness.
