MSC Seaside is a Seasideclass cruise ship currently owned and operated by MSC Cruises. As the lead vessel of the Seaside class, she lends her name to the company's Seaside class. At 153,516 GT, she would become the largest cruise ship ever to be constructed by Italian shipbuilder Fincantieri, and the 14th largest cruise ship in the world, behind Norwegian Epic, upon her delivery in December 2017.

On 22 May 2014, MSC Cruises announced that they had ordered two new 154,000 GT cruise ships from Fincantieri. The new order was based on the Seaside prototype, with each ship costing €700 million each.

On 17 March 2015, MSC Cruises announced that the new ship would be named MSC Seaside, lending her name to the class of the sister ships that would follow. It was also announced that she would be sailing yearround from PortMiami to the Caribbean.

Construction officially began on MSC Seaside with the celebration of the first steelcutting on 22 June 2015 at the Fincantieri shipyard in Monfalcone, Italy. On 4 March 2016, her keellaying was performed, in which the first 550ton block of the ship was laid, marking the beginning of the hull's assembly. Her coin ceremony was celebrated on 21 April 2016. The ship was floated out of the shipyard on 26 November 2016. She performed her first set of sea trials for 72 hours in lateAugust 2017 before finishing her final outfitting.