The first prisoners will be moved to HMP Berwyn in Wrexham on Tuesday - one of the biggest jails in Europe.
The new super-prison will eventually house up to 2,100 inmates and cost £250m to build.
The majority will be Category C, meaning they have been assessed as having a lower likelihood of escaping though some Category B prisoners could also be accommodated.
Its governor Russ Trent said his emphasis was on rehabilitation.
He added staff will refer to the prisoners as "men" and they will have "rooms" rather than cells.
The location was selected in September 2013, with people living near the former Firestone tyre factory site expressing worries about the effect on property prices and safety concerns.
Previously, an article published by the Institute of Welsh Affairs (IWA) said only a quarter of the inmates might end up being from Wales.
The Ministry of Justice said it was replacing "older, inefficient" buildings.
The Howard League for Penal Reform and other campaign groups have remained critical of so-called super prisons.
It says the high number of suicides and cases of self-harm among inmates show they do not work.
The construction of HMP Berwyn began in May 2015 and work is still under way on part of the site.
The prison is made up of three blocks, each housing 700 men, which will be opened in phases.