With the advancement of medical technology, the number of Children with Medical Complexity (CMC) has increased. Excursions with the CMC not only encourage children's social participation, but also have been shown to have a positive impact on their caregivers. However, the first-hand experience of the excursions has not yet been evaluated regarding the difficulties faced by CMCs and their caregivers during preparation, transportation, and in the local area. Semi-structured interviews were conducted with 8 informal and 8 formal caregivers of CMC who attended an excursion to Tokyo Disney Land (TDL) via video conference. We investigated challenges they had experienced through the excursion, performing inductive thematic analysis. Three themes were identified: preparation stage (Theme 1), problems encountered while traveling to the theme park (Theme 2), and problems at the theme park (Theme 3). In preparation stage, three sub-themes, i.e. preparation for the trip, cooperation with related parties, and researching about the theme park and asking for help, are reported. Theme 2 includes four sub-themes: activities of daily living, respiratory care, luggage, and weather changes, and also theme 3 have three sub-themes: activities of daily living, physical condition management, and issues for the theme parks. We found that securing power supply, location, and time for daily procedures are challenges in realizing CMC's excursions, but with sufficient preparation, it is possible in Japan without major troubles. However, it is also important to change the social environment to solve the issues.