Prisoners are detained in the least restrictive prison security settings as determined through risk assessment.
Having access to less restrictive prison security settings is important as it provides for the ‘normalisation’ principle  and thus reduces the risk of institutionalisation, making the transition to life on the outside easier. 
The Joint Committee on Justice and Equality (2018) recommended as follows:
There is a need for different mixes of restriction and supervision. Construction of future prisons should be done in a flexible manner, organised around self-contained units. Regimes should be programme-driven and open to the possibilities of individual change. Future infrastructural development within the prison system should involve the use of more innovative, community-based, semi-open facilities, avoiding the one-size- fits-all model. 
While there are currently two open prisons in Ireland, there are also some parts of the prison estate that operate a lower security regime. These include the Grove Unit in Castlerea Prison.
The Irish Prison Service has highlighted in its Capital Plan a need to “upgrade existing and develop a small number of new open, semi-open or low security centres in appropriate locations to supplement the minimal existing low-security capacity”. 
Indicator S5.1: the number of prisoners accommodated in low-security settings: In May 2018, 235 prisoners out of a total of 3,992 prisoners in custody were accommodated in low-security prisons.  Information provided by the Irish Prison Service shows that on the same date, a further 42 individuals were in the Grove Unit in Castlerea Prison, which is a low-security regime within a medium-security prison.
|Action 5.1:||The Department of Justice and Equality and the Irish Prison Service should increase the number of prisoners having access to less restrictive prison settings.|
Council of Europe Committee of Ministers (2003) Recommendation Rec(2003)23 of the Committee of Ministers to member states on the management by prison administrations of life sentence and other long-term prisoners, Principle 4 https://pjp-eu.coe.int/documents/3983922/6970334/CMRec+%282003%29+23+on+the+management+of+life+sentence+and+other+long+term+prisoners.pdf/bb16b837-7a88-4b12-b9e8-803c734a6117
Council of Europe (2016) Situation of Life-Sentenced Prisoners, European Committee for the Prevention of Torture and Inhu- man or Degrading Treatment or Punishment https://rm.coe.int/16806cc447
Houses of the Oireachtas (2018) Joint Committee on Justice and Equality: Report on Penal Reform and Sentencing, p. 53 https://data.oireachtas.ie/ie/oireachtas/committee/dail/32/joint_committee_on_justice_and_equality/reports/2018/2018-05-10_report-on-penal-reform-and-sentencing_en.pdf
Irish Prison Service, Capital Strategy 2016–2021, p. 26 http://www.irishprisons.ie/wp-content/uploads/documents_pdf/capital_strategy_2016.pdf
Irish Prison Service, 2018 Prison Populations, 31st May 2018, https://www.irishprisons.ie/information-centre/statistics-information/2015-daily-prisoner-population/2018-prison-populations/
Information provided by the Irish Prison Service Press Office on 1st June 2018