Measures aimed at preventing the COVID-19 virus from spreading restricted all aspects of public life, including possibilities for meeting in-person. Youth care professionals were forced to turn to telehealth tools, such as video calling and e-health methods, to be able to continue support and treatment of children, adolescents, caregivers, and families. This study consists of two qualitative interview studies on the experiences with and transition to telehealth during COVID-19: (1) interviews with youth care professionals (N = 20), and (2) interviews with adolescents who used mental health care support (N = 14). We specifically asked participants about five themes which were selected based on pre-COVID literature on telehealth: (1) tools (i.e., which programs are being used), (2) privacy, (3) methods (i.e., what was the same and what was different compared to in-person sessions), (4) relationship/therapeutic alliance, and (5) effectiveness (i.e., what was their impression of effectiveness of telehealth). The majority of professionals reported that they had very little to no experience with telehealth prior to the pandemic. Both professionals and adolescent clients mentioned benefits and limitations of telehealth. On several themes professionals and adolescent clients mentioned similar barriers in the transition to telehealth during COVID such as limitations of the available hard- and software (theme 1: tools); forced changes in the content and methods of the sessions (theme 3: methods); and difficulties with non-verbal communication (theme 4: alliance). However, whereas most professionals expressed the intention to keep using several aspects of telehealth after restrictions due to COVID are lifted, most adolescent clients expressed they see telehealth as a temporary solution and prefer meeting professionals in person. Their experiences and the barriers and enabling aspects they mentioned may provide important insights in the acceptability and usability of telehealth for youth care organizations, youth care professionals, researchers and higher educational training programs.