U.S. container imports plunged 6.6% year-over-year in September, signaling the start of a deeper and more sustained downturn in maritime trade as tariff pressures and shifting supply chains take hold.

Read also: U.S. Imports Slide 8.4% as China Trade Volumes Plunge Before Tariff Deadline

According to industry analyst John McCown, the ten largest U.S. ports saw their sharpest decline since early 2024, following modest gains of 0.2% in August and 3.2% in July—months buoyed by importers rushing to beat new tariff deadlines. Prior months had already shown contraction, with volumes down 8.3% in June and 6.6% in May.

“Inbound volume into the U.S. will show consistent and more pronounced year-over-year declines well into next year in the absence of any changes to the current tariffs,” McCown warned.

A temporary cushion came from a grace period allowing goods already at sea before August 7 to enter tariff-free if they reached U.S. ports by October 5. This exception muted the impact in late summer, particularly for long-haul shipments from Asia to the East Coast.

Global Supply Chains Rewire at Speed

McCown noted that companies are moving faster than expected to restructure supply networks in response to rising U.S. duties.

“If a manufacturing site wasn’t attractive before because of 10% higher costs, it suddenly looks appealing if it avoids 25% tariffs,” he said.

That realignment is reflected in global container data. While U.S. inbound traffic slumps, worldwide container volumes hit record highs for two straight months through August. Exports from the Far East rose 4.6% year-on-year, with strong import growth in Africa, the Middle East, India, and Europe—a stark contrast to weakening U.S. demand.

Double-Digit Declines Ahead

After a 15.2% surge in 2024, the National Retail Federation now expects U.S. inbound container volumes to fall 3.4% in 2025, with the final four months of the year down nearly 16% compared with 2024. McCown agrees the decline will intensify, predicting “double-digit drops at most U.S. ports” that could continue through 2026.

The Port of Los Angeles recorded a 7.6% decline in September—slightly better than its director’s 10% projection—while CTS data for August showed a 9.9% fall in total North American imports.

Tariff and Fee Fallout

The latest downturn comes even as reciprocal tariffs on Chinese goods remain paused until mid-November. However, President Donald Trump has threatened to impose a new 100% tariff on Chinese imports, heightening concerns for a market where China remains the dominant source of inbound U.S. containers.

Adding to the uncertainty, the U.S. Trade Representative’s ship fee plan, targeting Chinese-built or -operated vessels, took effect on October 14. Beijing swiftly retaliated with matching port fees on U.S.-linked ships. While few U.S.-built vessels are directly impacted, a clause concerning companies with 25% U.S. ownership could widen the fallout substantially if enforced strictly.

“The sheer number and complexity of the tariffs is a growing problem,” McCown said. “It’s affecting fluidity at terminals and within individual supply chains.”

A Reshaped Trade Landscape

As manufacturers and logistics operators adjust, the U.S. appears to be entering a prolonged phase of trade contraction and supply chain diversification. With container flows diverting to other global markets and tariff escalation looming, analysts warn that the coming year could mark a defining realignment in how—and where—goods move around the world.