Ocean carriers are changing vessel routings and service schedules to work around mounting constraints at the Panama Canal as tighter draft restrictions and fewer transit slots squeeze capacity.

Orient Overseas Container Line (OOCL) and CMA CGM have made recent adjustments to services that typically use the waterway, as the canal’s restrictions collide with weather-related disruptions at major Asian ports.

The result is a more fragmented trans-Pacific ocean freight market, with shippers increasingly weighing West Coast alternatives for cargo that would traditionally move through the Panama Canal to the East Coast.

After departing the Port of Xiamen in China last month, the OOCL Lilac opted to sail west through the Indian Ocean as part of its journey to the Port of New York and New Jersey rather than take the Panama Canal route typically used on the carrier’s South Atlantic Express service. The Journal of Commerce first reported the rerouting.

CMA CGM is taking a similar one-off approach with the CMA CGM Leo. After departing Shanghai Monday, the vessel is bypassing Panama and instead taking the Suez Canal on its way to the Port of Norfolk, Va., where it is expected to arrive around Oct. 1.

The carrier adjustments come as Asian ports are struggling with their own congestion in the wake of multiple typhoons that hit China in a span of several weeks, which forced shutdowns at some of the world’s busiest ports including Shanghai and Ningbo-Zhoushan.

Maritime research provider Sea-Intelligence found that global container vessel schedule reliability fell to 56.4 percent in July, a 6.1-percentage-point decline from June and the sharpest single-month deterioration since January 2021. The average delay for late vessels increased to 6.06 days.

The deterioration was especially pronounced at several major Chinese gateways. Only 21 percent of container vessels arrived on time at Shanghai in July, down 19.2 percentage points and the port’s lowest reliability in 14 years outside the pandemic-era disruptions, according to Sea-Intelligence. Ningbo’s reliability fell 20.1 points to 34.6 percent, while Yantian dropped 23.5 points to 48.3 percent.

A September Asia Pacific Freight Report from freight forwarder Dimerco estimates that the typhoons left 400,000 TEUs awaiting clearance at Shanghai, Ningbo, Yantian and Hong Kong. The report said average vessel waits reached three to eight days at Shanghai and two to four days at Ningbo, with congestion expected to persist into September.

“The trans-Pacific isn’t one market anymore—each port has its own balance point, and capacity is being removed involuntarily. That’s why slowing demand isn’t pulling rates down,” said Ted Chen, director of ocean freight at Dimerco Express Group. “Panama and Suez will decide where the market settles.”

That dynamic is particularly important as Panama’s own capacity tightens. The Panama Canal Authority reduced daily transit capacity to 34 vessels beginning Sept. 3, including nine Neopanamax and 25 Panamax slots. Panamax capacity is scheduled to fall to 23 daily slots beginning Sept. 15.

The canal’s current maximum authorized draft for the larger Neopanamax vessels is 48 feet. Depth at Gatún Lake, the manmade, rainfall-fed reservoir that feeds the canal’s lock system, sits at 84 feet, more than a foot below the September five-year average of 85.2 feet.

Dimerco said the draft restrictions are effectively splitting U.S. West Coast and East/Gulf Coast behavior and disadvantaging heavier cargo, adding another complication to an already disrupted trans-Pacific market.

The West Coast has become an increasingly important alternative as the restrictions go into effect. Last month, Port of Los Angeles executive director Gene Seroka estimated that Panama congestion could push roughly 5 percent more cargo toward West Coast ports in the near term.

But shifting cargo west does not eliminate the underlying capacity problem. Shippers must weigh additional transloading, trucking and inland transportation against the delays and draft limitations affecting East Coast routings.

The cost of securing Panama capacity is also rising. On the carrier side, Mediterranean Shipping Company (MSC) said it will revise its emergency Panama Canal surcharge to $100 per TEU beginning Oct. 1 on certain Europe-to-North America trades.

Prices continue to escalate for companies looking to skip the line if they haven’t booked a reservation to pass. The Panama Canal Authority (ACP) recently confirmed a Bloomberg report that South Korean liquefied petroleum gas (LPG) supplier SK Gas recently paid a record $5.3 million for an auction slot to traverse the waterway, highlighting the premium being placed on guaranteed access as available capacity tightens.

The outlook remains uncertain into 2027. The UN’s World Meteorological Organization (WMO) said Thursday that El Niño is expected to intensify in the coming months, potentially reaching exceptional strength before peaking toward the end of the year.

The WMO puts the likelihood of the pattern persisting through February 2027 at nearly 100 percent. The ACP has already cited El Niño among the factors behind its water-conservation measures, as below-expected rainfall continues to pressure the canal’s watershed.