As mentioned in Grounds for Detention, according to the Asylum Act, detention of asylum seekers requires an assessment of the individual circumstances of the applicant and of the possibility to effectively implement less severe alternative measures, thus demanding proof that alternatives to detention cannot be effectively applied. The Asylum Act lays down alternatives to detention consisting either of reporting duties before SEF on a regular basis or residential detention with electronic surveillance (house arrest).
Despite the safeguards enshrined in the law to ensure that detention of asylum seekers, including at the border, is used as a last resort and only where necessary, in practice, criminal courts rarely conducted an individual assessment on whether it is possible to effectively implement alternatives to detention. Even where the Criminal Court of Lisbon invited SEF to consider the release of families with children and their referral to CAR, the decisions systematically fell short of conducting an individual assessment of necessity and proportionality and of issuing an order to SEF.
Concerns regarding the judicial review of decisions to detain were flagged by the Ombudsperson in a hearing at the Parliament in 2020 (see Procedural Safeguards: Judicial review of the detention order).
In 2019, the practice was also condemned by the UN Committee Against Torture. It expressed concerns on multiple issues, including the excessive use of detention, the absence of individualised assessments as well as little consideration for alternatives to detention, the lack of adequate detention conditions in the relevant facilities, and entry fees charged to external parties at Lisbon airport. Among other detention-related observations, the Committee recommended that detention is used only ‘as a measure of last resort and for as short a period as possible, by ensuring individualised assessments, and promote the application of non-custodial measures’.
In 2020, the UN Committee on Human Rights, echoed concerns regarding detention at the border (namely regarding its duration and conditions), and recommended Portugal to ‘[e]nsure that the detention of migrants and asylum seekers is reasonable, necessary and proportionate […] and that alternatives to detention are found in practice.’
With the exception of the release of asylum seekers without conditions from the border, CPR is unaware of the application of alternatives to detention in practice.
 Article 35-A(2) and (3) Asylum Act. While the need for an assessment of the individual circumstances of the applicant is only mentioned in the case of detention on the grounds of national security, public order, public health or when there is a flight risk, it is difficult to conceive an assessment of less severe alternative measures for the remaining grounds for detention that is not based on the individual circumstances of the applicant.
 Article 35-A(4)(a) and (b) Asylum Act.
 Judicial Court of the Lisbon District, Local Misdemeanour Court of Lisbon – Judge 2, Applications Nos 3881/17.5T8LSB, 13 February 2017; 19736/17.0T8LSB, 11 September 2017; 22330/17.2T8LSB, 16 October 2017; 22779/17.0T8LSB, 20 October 2017; 23770/17.2T8LSB, 3 November 2017; 25058/17.0T8LSB, 20 November 2017; 25060/17.1T8LSB, 20 November 2017; 8909/19.1T8LSB, 29 April 2019.
 Ibid. para 40(a).