WASHINGTON—President Trump intends to nominate Lana Marks, a Palm Beach, Fla.-based handbag designer and a member of Mr. Trump’s Mar-a-Lago Club resort, to serve as the U.S. ambassador to South Africa.

The White House announced the selection, which had been rumored in recent weeks, in a statement Wednesday. The post has been vacant since the departure of Patrick Gaspard in December 2016. The U.S. mission has been overseen by Chargé d’Affaires Jessye Lapenn since then.

According to the White House, Ms. Marks, a South Africa native who attended the University of the Witwatersrand and the Institute of Personnel Management in Johannesburg, speaks both Afrikaans and the Xhosa language.

Ms. Marks doesn’t have previous diplomatic experience. Her company website touts her business background, including participation in the White House’s Women Business Leaders’ Forum. She has also represented the U.S. at a business forum in Finland and served on the Women’s Leadership Board at the Harvard Kennedy School of Government, according to her website.

Ms. Marks’s handbags retail for thousands of dollars, and her website boasts of celebrity clients. Ms. Marks’s company website also mentions her competitive international tennis career.