The purpose of the article is to substantiate educational strategies of collaboration, research and mentoring skills development in preservice teachers facilitating older adults' learning of ICT with the use of problem-based practice-oriented adult learning activities. The study involved students of Ukrainian and Polish universities who were in the first year of Master degree programme for preservice teachers and older people enrolled in the non-formal educational programme "The third age university". In order to identify the data on the initial levels of the target skills development in pre-service teachers, we used narrative interviews, a self-assessment questionnaire, and observations. At the stage of target skills development, we used the problem-based learning method which required the pre-service teachers to research the older adults' needs in ICT learning, provide mentoring and promote collaboration in the learning process. At the stage of evidence verification, we employed observation of pre-service teachers' behaviour and a self-assessment questionnaire and compared the results with the initial data. Our findings showed an increased level of the development of all the three skills of pre-service teachers, which confirmed the appropriateness of the use of the chosen learning method based on the authentic problem that was relevant to the pre-service teachers since they understood that its solution was important for the involvement of older citizens in active life of community and society undergoing digital transformation.