Persistent ocean congestion and delayed China-US tariff clarity are set to push additional cargo into Asia-Pacific air freight through the fourth quarter, with some Southeast Asia services from Incheon already requiring bookings up to two weeks in advance, Taiwanese forwarder Dimerco said in its October Asia Pacific Freight Report.

Dimerco frames Q4 as a "calm before the door opens," arguing that ocean shipping has not seen demand fall as quickly as supply chain disruption eased, extending the peak into a longer-than-typical stretch.

What is driving the projected mode shift?

Two forces sit behind Dimerco's call. Persistent ocean congestion continues to disrupt routings, leaving shippers with unreliable transit times. And China-US cargo that shippers held back while waiting for tariff direction will, once policy becomes clearer, need to move quickly — with air absorbing the volume that cannot make ocean cut-offs.

"Bookings look quiet right now, but that's the calm before the door opens," said Kathy Liu, vice president of global sales and marketing at Dimerco Express Group. "Once held-back China-US cargo releases and ocean congestion pushes shippers into air, the space will face some constraints."

Liu's framing carries commercial weight: forwarders selling Asia-origin air space to the US, Europe and intra-Asia lanes face a market that looks soft on the surface but holds latent demand that policy or weather events could release at short notice.

Which Asia origins are tightest?

Taiwan leads the report's tight-origin list. Strong demand for AI servers, semiconductors, high-performance computing equipment and electronic components keeps rates under upward pressure on US and intra-Asia lanes.

South Korea is the second pressure point. The Chuseok harvest festival has tightened space, with some Southeast Asia services from Incheon now requiring bookings two weeks in advance — a clear signal of capacity constraint at the origin.

Mainland China conditions diverge by trade lane. Pre-holiday and e-commerce activity tightens some regional routes, while US and Europe capacity remains more balanced across several origins. The China read differs sharply from the tightness described in Taiwan and South Korea.

How stretched is the rest of the region?

Across Southeast Asia, India and Australia, air capacity to the US remains tight from most origins:

• Singapore: backlog conditions
• Thailand: capacity reductions and flooding-related delays at Bangkok
• India: festive season pulling both air and ocean space to Europe and the US

The Bangkok situation adds a weather-driven risk layer that overlays the tariff and congestion story and could push more regional cargo to alternative gateways or to air at short notice.

What does this mean for shippers, carriers and forwarders?

Shippers face the risk of a sudden rate spike and capacity rationing if the tariff release coincides with continued ocean delays. Carriers operating from Taiwan, South Korea, Singapore, Bangkok and India benefit from current tightness, but carry the downside of demand stalling if tariff clarity arrives with negative economic signals. Forwarders are positioned to arbitrage between ocean and air, though the Dimerco call is precisely that air capacity is finite and about to tighten further.

What to watch next

Dimerco's view rests on tariff direction and ocean congestion continuing to push shippers into air as Q4 progresses. If either factor resolves sooner — a tariff deal or a sustained drop in ocean delays — the squeeze may not materialize. If both persist, the "calm before the door opens" framing points to a late-Q4 capacity event that shippers, carriers and forwarders should plan around.