Liner Service

A liner service is a regularly scheduled ocean freight service operating on a fixed route between designated ports according to a published timetable. Unlike tramp shipping, where vessels go wherever cargo is available, liner vessels sail on predetermined loops regardless of whether the ship is full or half-empty. The regularity and predictability of liner services form the backbone of global container shipping, allowing importers and exporters to plan their supply chains around known departure and arrival dates weeks or months in advance.

How Liner Services Operate

Each liner service is identified by a name or code assigned by the operating carrier or alliance. Maersk’s TP6 service, for example, follows a specific rotation through several Asian ports before crossing the Pacific to the U.S. West Coast. A single rotation on a major Asia-to-U.S. West Coast service takes approximately 28 to 35 days port-to-port, with the full loop (outbound and return legs) running 56 to 77 days. Carriers deploy a fleet of vessels to each service, typically 8 to 12 ships per loop, so that a departure is available every seven days from each port on the rotation.

The three major shipping alliances, 2M (Maersk and MSC), Ocean Alliance (CMA CGM, COSCO, Evergreen, OOCL), and THE Alliance (Hapag-Lloyd, ONE, Yang Ming, HMM), operate overlapping liner services on the world’s major trade lanes. Alliance members share vessel space, which increases frequency and port coverage without each carrier having to deploy its own ships on every route.

Schedules and Port Rotations

A liner service’s port rotation is published in advance and updated periodically based on demand patterns and operational efficiency. A typical Asia-to-U.S. West Coast string might call at Ningbo, Shanghai, Busan, and then proceed to Long Beach and Oakland before returning. The published schedule shows expected arrival and departure dates for each port, allowing shippers and freight forwarders to book cargo based on the vessel’s estimated departure (ETD) and estimated arrival (ETA) at the relevant ports.

Schedule reliability has been a sore point in the industry since the disruptions of 2020 through 2022. At the worst points during the pandemic-era congestion, on-time performance for major liner services dropped below 35%, meaning more than six out of every ten vessel arrivals were delayed. By 2024, reliability recovered to the 50% to 65% range on most trade lanes, but it remains far below the 80%+ that shippers experienced pre-pandemic.

Pricing and Rate Structures

Liner services quote freight rates per container (per TEU for 20-foot containers, per FEU for 40-foot containers). Rates vary by trade lane, season, and demand. A spot rate from Shanghai to Los Angeles might range from $1,500 to $8,000 per FEU depending on market conditions. Contract rates, negotiated annually or semi-annually between shippers and carriers, typically run lower than spot rates in tight markets but may be higher when spot rates drop during slack seasons.

Additional charges layer on top of the base freight rate: bunker surcharges (BAF), terminal handling charges (THC) at origin and destination, peak season surcharges (PSS), and equipment imbalance surcharges when carriers need to reposition empty containers. These surcharges can add $500 to $2,000 per container on top of the base rate.

Blank Sailings and Schedule Changes

Carriers manage capacity by “blanking” sailings, canceling a scheduled departure when demand does not justify running a full vessel. During low-demand periods, carriers on a weekly service might blank every third or fourth sailing to keep utilization and rates stable. Blank sailings are typically announced two to four weeks in advance, but short-notice cancellations do occur and can disrupt shippers who had already booked and delivered cargo to the origin port terminal.

Impact on FBA Sellers

Amazon sellers importing goods from Asia rely on liner service schedules to plan inventory replenishment. A seller who knows their product takes 25 days ocean transit plus 5 days for drayage and prep can calculate that a container booked on a specific vessel departure will have inventory at MeisterPrep’s Long Beach warehouse by a known date, prepped and forwarded to Amazon FBA on a predictable timeline. When liner services run on schedule, this planning works. When vessels arrive five to ten days late or sailings are blanked, the seller’s inventory replenishment cycle breaks, potentially causing stockouts during peak selling periods.