Container volumes at major U.S. ports rose 1.7% year-over-year in the first half of 2025, driven by a surge in preloaded imports ahead of tariff hikes, while exports continued to decline amid ongoing trade headwinds.

Volumes at the nine largest U.S. ports rose to 16.9 million TEU in the January to June period this year as importers rushed to beat rising tariffs, according to BIMCO Chief Shipping Analyst Niels Rasmussen.

Import volumes grew 4.3%, influenced by preloading in anticipation of tariff increases, while export volumes declined by 4.2%.

BIMCO, which represents 60% of the global fleet, cited data from Yale's Budget Lab showing the effective U.S. tariff rate climbed from 2.4% in January to 3.7% in February, 8.9% in March, and 26.0% in April, following the "Liberation Day" announcement of U.S. President Donald Trump.

The global shipping association representing 60% of the world's fleet cited the Budget Lab at Yale reported that the effective US tariff rate was 2.4% in January 2025 before subsequent tariff increases raised it to 3.7% in February, 8.9% in March, and 26.0% in April following the “Liberation Day” announcement.

Later, reductions and implementation delays brought the effective import tariff rate down to 21.1% in May and 15.7% in June.

"Import volume growth during the first half reflected changes in tariff rates, with the use of bonded and free zone warehouses allowing some importers to avoid higher tariffs. Import volume rose 10.0% year-over-year in the first four months but declined 6.2% during May and June," said Rasmussen.

The BIMCO report noted that US West Coast ports benefited most from preloading early in the year and saw a 14.4% year-over-year increase in import volumes during the first four months. However, the ports also suffered most from the subsequent volume correction as volumes declined 9.2% year-over-year in May and June combined.

Despite the gains in the first half of 2025, total import volumes remained below 2021 and 2022 H1 levels, when volumes peaked during the COVID pandemic.

Rasmussen noted that although only China and Canada implemented tariffs in response to US actions, export volumes from the nine largest US container ports decreased by 4.2% year-over-year in the first half of the year.

This decrease is part of an ongoing trend, as export volumes have fallen each year since 2018, except for a 7.4% increase in the first half of 2024. Export volumes during the first half of 2025 therefore ended 12.5% lower than in 2018.

"Despite some new trade agreements, the average effective US tariff rate on August 1 is estimated at 17.6%, about two percentage points higher than in June, when imports fell 5.8% year-over-year," Rasmussen said.

"Concurrently, average spot freight rates from Shanghai to the US (SCFI) have dropped over 60% since early June, also indicating continued import weakness during the third quarter, which could extend into the rest of the year," he added.