Coca-Cola Co. reported rising drink volumes in its latest quarter, boosted by demand for diet sodas in the U.S. and by experiments abroad. But it also said it would take the unusual step of raising prices on its carbonated soft drinks in the middle of the year.

Chief Executive James Quincey said the price move in North America was in response to rising costs, including higher freight rates and metal prices after the U.S. placed tariffs on Chinese imports earlier this year.

“There...