Container ships departing from China for the United States are once again experiencing a surge in demand, with space fully booked and orders lining up through June, said forwarders and executives of shipping companies.

They said the primary factor driving this uptick is a notable increase in demand for the US routes. In addition, the announcement made by China and the US on May 12 to mutually lower tariffs provided a much-needed boost, spurring many previously cautious businesses to take actions and revive suspended orders.

When Washington announced tariff increases in early April, a large number of US companies chose to delay their purchasing plans rather than cancel orders outright, said Jiang Lei, executive director of Zhejiang Xinqiaoyuan International Logistics, a forwarder based in Ningbo in East China's Zhejiang province.

As China and the US agreed temporarily to lower tariff rates, Jiang said that many US businesses have promptly resumed placing orders with Chinese suppliers.

Based on the export volume of Ningbo-Zhoushan Port, the world's third-largest in terms of container throughput volume in 2024, the freight index between May 24 and Friday for the US East Coast stood at 2,490 points, up 69.7 percent from the previous week, while the index for the US West Coast reached 3,585.2 points, soaring 89.2 percent from the previous week, according to the latest index figures released by the Ningbo Shipping Exchange in Zhejiang.

According to the feedback from forwarders and exporters, current rates for shipping space to the US continue to rise, with shipping companies charging over $6,000 per 40-foot equivalent unit to the US west coast and over $8,000 to the US east coast, according to Ningbo Customs.

Qian Long, head of Topocean Consolidation Service (China), a subsidiary of California-based supply chain solution provider Topocean Group, said that in late April, freight volumes to the US fell sharply due to tariff-related factors, prompting shipping companies to adjust their capacity, with many canceling US-bound sailings and redeploying ships to other routes.

"As cargo volumes have now rebounded, the capacity situation has quickly reversed. Shipping companies are working hard to allocate capacity and increase space availability," said Qian, adding that some vessels, however, are still on their return voyages, intensifying the supply-demand imbalance in the short term.

In another development, the Office of the US Trade Representative announced on Saturday the extension of exclusions in the Section 301 investigation of China's acts, policies and practices related to technology transfer, intellectual property and innovation. The exclusions were previously scheduled to expire on Saturday. They have been extended through Aug 31.

This move indicates that some products covered by the exclusions, such as solar panels and blood pressure monitors, are critical to US industries. Maintaining exclusions for these items helps prevent supply chain disruptions and supports domestic economic stability within the US, said Gao Lingyun, a researcher specializing in international trade at the Chinese Academy of Social Sciences in Beijing.

Silvia Ding, managing director for China at Danish shipping group Maersk Line, said that to ensure stability for its supply chain operations, Maersk began to ramp up capacity on the China-US routes in mid-May, and the number of bookings continues to rise.

"During the period of tariff fluctuations, there was a significant increase in cargo volumes from China to Latin America, Africa, Southeast Asia and the Middle East," said Ding, noting this effectively offset the impact of fluctuations on a single route.

Yang Yanbin, deputy general manager of the production and operations unit at Shanghai International Port (Group), said that from May 19 to 25, the container throughput for US-bound exports, in face of surging demand, reached 59,000 containers, up 49.4 percent from the previous week.

All previously suspended US-bound sailings have now resumed, bringing the number of weekly sailings on US routes at the port back to the normal level of 42, said Yang.

The North American routes will continue to bustle in June. Shipping companies, including Germany's Hapag-Lloyd and France's CMA CGM, report a notable upward trend in bookings for US routes, Ningbo Customs said last week.

The surging demand on China-US shipping route reflects a shared belief among businesses on both sides that mutually beneficial cooperation remains the cornerstone of their commercial ties, said Lin Meng, director of the modern supply chain research institute at the Beijing-based Chinese Academy of International Trade and Economic Cooperation.