The MS Victoria has 739 rooms and will initially house between 1,600 and 1,700 people.
About 9,000 refugees have made their way to Scotland since war broke out in Ukraine.
But earlier this month the Scottish government had to suspend its super-sponsor scheme due to a shortage of suitable housing.
Shona Robison, cabinet secretary for social justice, housing and local government, said the “safety and welfare of displaced people from Ukraine, who are primarily women and children who may have experienced much stress and trauma, is of paramount importance”.
The vessel has been chartered as part of a £6.7m deal with Bradford-based firm Corporate Travel Management (North).
Ms Robison said: “We do not want people spending more time in temporary accommodation, such as the ship, for any longer than is absolutely necessary.
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“But we want to make them as comfortable as possible during their stay and we have worked with partners to provide a variety of services on-board for guests in addition to the support services available.
“These will include restaurants, child play facilities with toys and books, shops, laundry, cleaning, wi-fi access and communal spaces.”
The MS Victoria has been chartered until January 2023.
The Scottish government said the ship could house a maximum of 2,200 people, and the number was being kept under review.
Residents will be able to arrive and leave whenever they want and the vessel will be docked at all hours.
‘Warm Scottish welcome’
The government said there would be a “security perimeter around the ship with proportionate security and identification checks for people moving on and off the ship”.
It said there were about 115 new arrivals from Ukraine each day in the week to 19 July.
Ms Robison said it showed the “success” of the super-sponsor scheme and, with thousands with a Scottish sponsor already in the country, “accommodating them all is always going to be a challenge”.
She added: “I am proud of the support that Scotland is providing the people from Ukraine and I want to thank everyone who has been involved, from those helping to prepare the ship for use, those providing support services and to the people opening up their homes to provide Ukrainians with a warm Scottish welcome.”
Originally, the Scottish government committed to welcome 3,000 when the super-sponsor scheme launched in March.
As of 19 July, there had been 35,085 applications under the super-sponsor scheme and 23,811 visas issued.