Container carriers are reducing vessel speeds as high bunker prices add pressure to voyage costs, according to Alphaliner.

From Q4 2025 to mid-April, average container ship speed fell by 2.3%, moving from 15.6 knots to 15.2 knots. The figure was included in a report issued on Wednesday.

The decline became sharper after late February, when attacks involving Iran and US forces coincided with lower operating speeds. On 14 April, average speed reached 15.2 knots, the weakest level since March 2023.

Fuel prices rose sharply over the same period. In Singapore, VLSFO reached $1,201/mt on 13 March, while LSMGO stood at $2,018/mt on 3 April.

According to Ship & Bunker, Singapore VLSFO later eased after the US and Iran announced a temporary ceasefire, falling to $764/mt on 28 April.

Fuel is one of the main voyage cost items for container shipping. As a result, slow steaming has returned as a practical cost-control measure, with operators running vessels at lower speeds to reduce fuel consumption.