
Coetzee, 51, will join Japanese club, Kobe Steel Kobelco Steelers, having decided to put pen to paper this week.
"I have always said that I would make an announcement once I had made a decision about my future and my decision has now been made and communicated properly," said Coetzee on the official DHL Stormers website.
Under the guidance of Coetzee, who has been head coach of DHL WP since 2008 and the DHL Stormers since 2010, the DHL Stormers have become one of the most consistent Vodacom Super Rugby teams on the circuit.
At Absa Currie Cup level, meanwhile, DHL Western Province have won two titles under Coetzee's leadership - in 2012 and 2014 - having, in total, contested four finals in the past five seasons, with two of those finals being at home and in succession.