He will be succeeded by his cousin Tim Wates, who is currently deputy chairman.
Sir James said: “I have enjoyed my 10 years as chairman enormously, and the time is now right to pass the baton over to my cousin Tim.
“I look forward to continuing to serve on the board and being actively involved in the business, including representing Wates in external forums.”
Tim Wates said: “It is an honour to be named the next Chairman of our 125-year-old enterprise and continue our tradition of maintaining a long-term perspective and commitment to business as a force for good in society.”
Tim joined Wates in 1993 after starting his career in banking with Cazenove & Co, and has served on the board from 2006 to 2008 and since 2011.
He was appointed deputy chairman in October 2022 and has served as the lead family director on housing issues.