According to Article 81(2) FNIA, ‘detention shall take place in detention facilities intended for the enforcement of preparatory detention, detention pending deportation and coercive detention. If this not possible in exceptional cases, in particular because of insufficient capacity, detained foreign nationals must be accommodated separately from persons in pre-trial detention or who are serving a sentence’.  In a judgment issued in March 2020, the Federal Supreme Court stated that detention for immigration related purposes must take place in facilities specially dedicated and conceived for this scope and that detention in a non-specialised facility – even in a separated section – is only admissible for a short time, in exceptional and well-founded cases.
However, the administrative detention of asylum seekers and other foreigners in prisons that are also holding prisoners under the penal code – usually in separated areas – is still a very frequent solution adopted by cantons. Following this judgment, this practice should be considered unlawful.
Specialised facilities, prisons and pre-trial facilities
In practice, asylum seekers are regularly detained in prisons or pre-trial detention facilities as there are very few detention centres used exclusively for immigration detention. To this latter category currently belong only three facilities: Frambois (20 places) and Favra (20 places) in the canton of Geneva, and the regional prison of Moutier in the canton of Bern (30 places). While Favra and Moutier have been strongly criticised in the past,  the detention centre of Frambois has by far the most liberal detention conditions in Switzerland. Resulting from an inter-cantonal cooperation (“Concordat”) of three cantons (Geneva, Vaud and Neuchâtel), it is the only detention centre that is not a (former) prison. A few other facilities detain exclusively foreigners in administrative detention but are situated right next to and managed together with a prison for penal use. It is the case of Bässlergut (Basel City, 40 places), Crêtelongue (Valais) and the Centre for the administrative detention of foreigners in Zurich (at Zurich-Kloten airport), the latter having a capacity of 130 places. In addition to these facilities, many ordinary prisons confine immigration detainees under the same roof as convicted or remand prisoners, mostly in separated sections, but sometimes also in cells that are not specifically foreseen for this form of detention.
Since the detention of asylum seekers in Switzerland takes the form of pre-removal detention, there is no specialised facility for asylum seekers only, but asylum seekers are detained together with irregular migrants and foreign nationals without or having lost their residence permit.
Given the decentralised nature of immigration detention in Switzerland, it is difficult to provide for a list of the facilities used for this purpose. According to a 2018 report of monitoring in the area of liberty deprivation, there were 22 facilities carrying out immigration detention, including separate sections within prisons, totalling a capacity of 352 places. More recent data on the number of facilities is not available. The number of places dedicated to immigration detention is 277.
The number of 22 facilities is probably an underestimation since it only includes facilities that permanently reserve some places for immigration detention, but it can also happen that other facilities hold immigration detainees for a few days. Indeed, in the 2019 Catalogue of penitentiary establishments published by the Federal Statistical Office, 13 additional facilities are said to be used for the execution of detention under the FNIA.
Following the above cited case law and critique by national and international institutions, there is currently a certain tendency to centralise immigration administrative detention in fewer facilities allowing to better comply with national and international norms. For example, in the canton of St. Gallen the old detention centres of Widnau and Bazenheid, that had been strongly criticized by the NCPT, have been closed in 2022 and a new specialised detention centre is planned in Altstätten.
Airport transit zones
The SEM should provide persons who lodged an asylum application at the airport with a “place of stay and appropriate accommodation” in case entry is temporarily denied. Maximum stay in the transit zone is 60 days in total. The centre in the transit zone of Geneva airport has a capacity of 30 places. For the purpose of this report, we qualify these as detention centres, although people are not formally detained and can leave the centre and remain in the airport transit zone in principle.
Reception centres in isolated areas
As detailed in Freedom of Movement and The question of de facto detention in Switzerland accommodation in federal asylum centres that are located in isolated areas may be considered as constituting de facto detention in some cases. See also Types of Accommodation.
 This formulation was introduced on 1 June 2019 in order to align with Article 16(1) of the Return Directive and interpretation of the CJEU and sets a clearer framework for immigration detention, which requires specialised facilities.
 Federal Supreme Court, Decision 2C_447/2019, 21 March 2020. In the case under exam, the Court ruled that Articles 81(2) FNIA had not been violated because detention was short (4 days) and motivated (facilitating transportation to the airport).
 Jörg Künzli, Kelly Bishop, Ausländerrechtliche Administrativhaft in der Schweiz: Menschenrechtliche Standards und ihre Umsetzung in der Schweiz, Swiss Centre of Expertise in Human Rights, Bern, 28 May 2020, 4, available at: https://bit.ly/3HCCjcY.
 NCPT, Bericht an den Regierungsrat des Kantons St.Gallen betreffend den Besuch der Nationalen Kommission zur Verhütung von Folter in den Gefängnissen der Kantonspolizei St.Gallen vom 5. und 6. Oktober 2015, 17 March 2016, 9; NCPT, Bericht an den Regierungsrat des Kantons Bern betreffend den Besuch der Nationalen Kommission zur Verhütung von Folter im Regionalgefängnis Moutier vom 28. Juni 2019, 1 April 2020, available at: https://bit.ly/3DjPltn. See also Decision 2C_765/2022, 13 Ocotober 2022 on the Regional prison of Moutier.
 See the website on the inter-cantonal cooperation of the Heads of the police and justice Departments of the “Latin cantons” that also contains a description of the detention centre: La Conférence latine des Chefs des Départements de justice et police (CLDJP), available at: https://bit.ly/2JbO8YG. The legal basis for the detention centre and a description of the centre may is available at: https://bit.ly/2QzOSLt.
 Jörg Künzli, Kelly Bishop, Ausländerrechtliche Administrativhaft in der Schweiz: Menschenrechtliche Standards und ihre Umsetzung in der Schweiz, Swiss Centre of Expertise in Human Rights, Bern, 28 May 2020, p. 4, available at: https://bit.ly/3HCCjcY.
 Parliamentary Control of Administration, 7552.
 Federal Office of Statistics, Catalogue des établissements pénitentiaires. Last update on January 2020, available at: https://bit.ly/3tmayLA. The new digital version of the Catalogue does not provide for this information.
 Article 22(5) AsylA.
 SEM, Handbook on Asylum and Return, chapter C2, 4.