Introduction: In Japan, telemedicine has gradually expanded due to deregulation in response to the COVID-19 pandemic. However, its current status remains unclear, as it is primarily provided by general practitioners. This study aims to examine the use of telemedicine in sublingual immunotherapy (SLIT) for patients with Japanese cedar pollen allergy and/or house dust mite allergic rhinitis. Methods: We conducted a retrospective analysis of medical record data from seven otorhinolaryngology clinics and performed an exploratory evaluation between a group that combined telemedicine and in-person visits during the initial 6 months of SLIT and another group with only in-person visits. Results: Following propensity score matching, 51 and 82 patients were eligible for the telemedicine and in-person groups, respectively, with 33 cases in both groups. Both groups had similar characteristics after matching. No significant difference was found in the withdrawal rate at 6 months from the start of SLIT (6.1% and 9.1% in each group; p = 1.00), side effects, or treatment efficacy between the two groups. The average copayment for patients tended to be significantly higher in the telemedicine group after one, three, and 6 months following SLIT initiation. Discussion: The situation of patients who receive an appropriate combination of telemedicine and in-person visits is not significantly different from patients who receive in-person visits alone. This study may help indicate the actual status of telemedicine in Japan. Further investigation at more facilities is necessary in the future to dispel concerns in the practice setting.