PURPOSE: Mobile technology is increasingly being used to widen access to and support the delivery of public health interventions. Human immunodeficiency viruses (HIV) self-testing (HIVST) enables individuals to have autonomy. We evaluated the feasibility of a novel application called ITHAKA to support HIVST among youth aged 16-24 years in Zimbabwe. METHODS: This study was nested within a trial of community-based delivery of integrated HIV and sexual and reproductive health services called CHIEDZA. Youth accessing CHIEDZA were offered provider-delivered HIV testing or HIVST supported by ITHAKA, either on a tablet on-site at a community centre or on their mobile phone off-site. ITHAKA incorporated pre and post-test counselling, and instructions for conducting the test and the appropriate actions to take depending on test result, including reporting HIV test results to health providers. The outcome was completion of the testing journey. Semistructured interviews with CHIEDZA providers explored the perceptions of and experiences with the application. RESULTS: Between April and September 2019, of the 2,181 youth who accepted HIV testing in CHIEDZA, 128 (5.8%) initiated HIVST (the remainder opting for provider-delivered testing) using ITHAKA. Nearly all who performed HIVST on-site (108/109 (99.1%)) compared to only 9/19 (47.4%) who tested off-site completed their testing journey. Low digital literacy, lack of agency, erratic network coverage, lack of dedicated phone ownership, the limited functionality of smartphones challenged implementation of ITHAKA. DISCUSSION: Digitally supported HIVST had low uptake among youth. The feasibility and usability of digital interventions should be carefully assessed before implementation, paying careful attention to digital literacy, network availability, and access to devices.