Siem Offshore has sold a multipurpose field and ROV support vessel (MRSV) to buyers in Nigeria.
The Oslo-listed owner has signed an agreement to sell the 4,214-dwt Siem Marlin (built 2009) for an undisclosed price.
The buyer is Lagos-based Marine Platforms, an oil services company that operates in Nigeria and the African continent, according to its own website.
"The agreement is made at market terms," Siem Offshore said in a filing on Monday.
VesselsValue.com estimates the Kleven Verft-built ship's market value at $25.56m.
The vessel is scheduled for delivery to its new owner this week.
Sales by Siem have been few and far between. Its last transaction was seen in January, when the company sold the three oldest ships in its fleet for $10m en bloc.
Kristian Siem returned as chairman of Siem Offshore's board at the end of July, replacing Eystein Eriksrud, who has stepped down.