Taiwanese forwarder Dimerco predicts persistent ocean congestion and a release of tariff-held China-US cargo will push more freight into air transport as the fourth quarter progresses, tightening capacity that is already under strain across Northeast Asia.

The forecast comes in Dimerco's October Asia Pacific Freight Report, which frames the coming weeks as a window in which two separate forces converge on the air cargo market: shippers abandoning congested ocean services, and China-US shipments held back by tariff uncertainty finally moving.

"Dimerco expects clearer tariff direction and persistent ocean congestion to potentially push more cargo into air as Q4 progresses," the company said.

What is driving the ocean-to-air shift?

Dimerco attributes the prolonged ocean peak to a combination of supply chain disruption and demand that has not slowed as quickly as expected. The result: the quarter's peak has stretched out, and shippers needing capacity and speed face a realistic case for paying airfreight rates instead.

The tariff factor compounds this. Shipments between China and the US held in limbo by trade-policy uncertainty will be released once the situation clarifies, Dimerco argues. Because of time constraints, cargo originally booked for ocean may move by air instead — tightening air capacity further.

Kathy Liu, vice president of global sales and marketing at Dimerco Express Group, offered a blunter read of current conditions.

"Bookings look quiet right now, but that's the calm before the door opens. Once held-back China-US cargo releases and ocean congestion pushes shippers into air, the space will face some constraints," Liu said.

Which markets are already tight?

Demand from AI, semiconductor and year-end retail supply chains is keeping capacity constrained at many origins, with Northeast Asia the standout region.

• Taiwan: Strong demand for AI servers, semiconductors, high-performance computing equipment and electronic components is putting upward pressure on rates on US-bound and intra-Asia lanes.
• South Korea: Conditions tightened around the Chuseok harvest festival, with some Southeast Asia services from Incheon requiring bookings up to two weeks in advance.
• China: A mixed picture. Pre-holiday and e-commerce activity is tightening some regional routes, while US and Europe capacity remains more balanced at several origins.
• Southeast Asia, India, Australia: Air capacity to the US is tight from most origins. Singapore faces backlog conditions, Thailand is dealing with capacity reductions and flooding-related delays at Bangkok, and India is entering its festive season with both air and ocean space constrained to Europe and the US.

What happens next?

The near-term trajectory Dimerco sketches is one of tightening rather than loosening: quiet bookings today, followed by a capacity squeeze once tariff direction clears and ocean congestion continues to divert time-sensitive freight into the air network. How sharply rates respond will depend largely on when the China-US tariff picture settles.