The ship previously operated on the Irish Sea, between Birkenhead and Belfast, as Stena Mersey.

Stena Baltica was launched in December 2005 as Mersey Viking, entering service with Norse Merchant Ferries later the same month.

Mersey Viking received Norfolkline lettering on her red hull but retained her Norse Merchant Ferries funnel for several years.

Later that same year, DFDS sold its Northern Irish operations to Stena Line.

Stena Baltica is planned to operate on the Baltic Sea between Nynäshamn and Ventspils.