A logjam in the global shipping industry is testing the resilience of China’s exporters, who have driven the country’s economic recovery by churning out goods to meet surging global demand during the Covid-19 pandemic. That demand in recent months has outpaced the capacity of a global shipping industry that has been slowed by pandemic safety measures. Chinese exporters have been paying sharply higher rates and struggling to find containers for their goods.

Chen Yang, who runs a textile trading unit at a state-owned enterprise in the southern city of Hefei, said the business, which mostly exports to the U.S., has weathered the pandemic and the China-U.S. trade war, but he expected to lose money in 2020 in part because of a sharp rise in shipping costs.

A 40-foot container arriving at the port of Charleston, S.C., in December cost Mr. Yang around $7,500, up from $2,700 in April, he said. He also has to book space on the vessel at least 20 days in advance, more than double the usual time. “I have never seen anything like this in my 18 years of experience as an exporter,” said Mr. Yang. “We’ve been operating at a loss since August.”