Sea-Intelligence has logged a sharp deterioration in container liner schedule reliability, with the Denmark-based analytics firm pinning the slide on congestion at Asian ports.

The finding lands as shippers, forwarders and BCOs head into peak-season planning with carrier schedules already under strain. Sea-Intelligence's Global Liner Performance series is the industry's standard read on on-time arrivals, publishing carrier-by-carrier, alliance and trade-lane cuts that feed contract talks, BCO RFPs and forwarder capacity planning.

What does Sea-Intelligence actually measure?

The firm tracks vessel on-time performance against published schedules across the major east-west and north-south trades. A vessel counts as on-time if it arrives within a calendar-day window of its advertised berth call. The dataset covers the top container operators and the largest alliances, with monthly releases to subscribers.

That methodology makes Sea-Intelligence the reference read for service-level disputes. When a BCO argues a carrier missed contract terms, the dispute often turns on the firm's numbers.

What's driving the latest drop?

Asian hub ports anchor east-west rotations. When vessels bunch at these terminals, sometimes queueing days outside berth, schedules slip across every downstream call. A delayed load port pushes back the next string of port calls, and by the time the ship reaches North Europe or the US West Coast, reliability has eroded across the loop.

Singapore, Busan and other Asian transshipment hubs sit at the center of east-west networks. When any of those nodes tightens, delays compound across the Asia-Europe strings and the transpacific pendulum services that link them to North America.

What does it cost shippers?

Schedule reliability drives inventory positioning. A reliability decline forces BCOs to hold more safety stock, pay more demurrage and detention at destination, and book earlier — often at premium rates. Retailers running lean programs feel it first through stockout risk.

Forwarders absorb the customer-facing damage. Their transit-time promises depend on carrier performance the carriers cannot currently deliver. Spot rates typically firm when reliability slides, because shippers who cannot trust the schedule pay up for guaranteed space and equipment.

How do carriers read this?

Carriers see reliability losses translate into service-level complaints from major accounts. The upside: congestion-driven capacity tightness supports rate levels on Asia-Europe and transpacific lanes, where operators have already pushed several General Rate Increases through this year.

The carrier-level split Sea-Intelligence publishes matters for BCO contract talks. Wide variation persists across operators, and any gap widens when Asian hubs congest. Disciplined carriers absorb delays and protect on-time numbers. The rest lose weeks on every rotation.

What's the trajectory?

Three signals will tell shippers what comes next:

• The next Sea-Intelligence release, confirming whether the drop has bottomed or deepened
• Anchorage data from the major Asian hubs, showing whether waiting times are rising or easing
• GRI filings and peak-season surcharges, indicating whether carriers plan to monetize the congestion or absorb it

Reliability rarely recovers fast. Once schedules slip, rotations need several sailing cycles to reset, and carriers cannot simply add vessel capacity when a hub stays clogged. Peak season will magnify every delay, and tight-rotations will struggle to insert extra sailings. The next quarter's data could show further erosion before any rebound — a prospect that will keep BCOs and forwarders cautious on capacity commitments through the rest of the year.