Mariella was the world's largest cruiseferry from 1985 until 1989, when the accolade passed on to her Viking Line fleetmate MS Athena.

[7] When the Mariella was delivered in 1985, she was the first ship on Viking Line's Helsinki–Stockholm service which was not owned by Rederi Ab Sally.

In 1989, ahead of the delivery of the new MS Cinderella, SF Line considered moving Mariella on to a proposed express Helsinki–Norrköping service aimed at passengers travelling with their cars.

As Åland is not a part of the EU tax union, Viking Line could continue tax-free sales on its ships.

In September 2000 Mariella was refitted at Naantali with rear sponsons and a new fast rescue boat.

Her interior was also brought up to date and for some time after the refit she sported the text "Updated 06/10 2000" on her hull.