Background <p>While knowledge of telepsychotherapy increased during the COVID-19 pandemic, little is known about face-to-face psychotherapy conducted under infection prevention measures. This study examined the impact of infection prevention measures on face-to-face psychotherapy and how these difficulties led psychotherapists to devise the support measures.</p> Method <p>An online survey of 471 Japanese psychotherapists was conducted. Analysis items included COVID-19 infection prevention measures, changes in the structure of psychotherapy, difficulties and concerns in face-to-face psychotherapy caused by infection prevention measures, devices for overcoming difficulties.</p> Results <p>The structural analysis of covariance showed that although the face masks did not affect the difficulties in psychotherapy, there was a significant positive effect on the difficulties in communication and stable psychotherapy due to both the shielding board separating client and psychotherapist and the reduction in time and number of face-to-face psychotherapy sessions. In addition, there was a significant positive effect on communication devices and verbalization due to difficulties in stable psychotherapy, via concerns about identity as a psychotherapist and concerns about communication.</p> Conclusions <p>A shielding board separating client and psychotherapist inhibited the mutual exchange of information and the maintenance of stable support. In addition, reducing the frequency and duration of sessions caused difficulties in communication and support stability. Maintaining ongoing psychotherapy through alternative methods such as telepsychotherapy is critical when face-to-face sessions are limited. When psychotherapists experienced difficulties in maintaining stable support and communication, they developed adaptive strategies such as overacting and validating, both directly and through professional identity concerns, to enhance face-to-face psychotherapy.</p>