Animal-assisted and nature-based interventions in psychosocial treatment for various groups of clients have been studied internationally. However, there is little knowledge about how young adults with autism experience participation in such types of interventions. This clinical study aimed to describe the feasibility of animal-assisted and nature-based activities on a farm as a complementary intervention for young adults with autism and social withdrawal. The participants were aged 18-30 years, diagnosed with autism and social withdrawal, with no organised occupation during the previous year. Eleven of 13 participants completed a 12-week intervention in small groups. They took part in interviews before and after, which focused on their current life situation and expectations about, and experiences of the intervention. The feasibility was described in terms of participants' characteristics, attendance, and their experiences of participating in the activity. Data were analysed with descriptive statistics and qualitative content analysis. The intervention was formed in collaboration with participating supervisors, ordinary clinical staff, and a young woman with a user perspective. The level of feasibility was found to be high. The mean participation rate during the activity days was 75% and varied from 50 to 100%. The analysis of the participants' experiences from the activity generated three categories, "Being in a meaningful context", "Creating a comfort zone" and "Developing structure in everyday life", and each of these included sub-categories. The main categories revealed a dynamic process based in meaningfulness, comfort and structure in everyday life. The positive experiences of undemanding activities, emotional relationships and non-verbal communication with the horses were prominent and might facilitate the development of social interaction. However, the intervention's timeframe of 12 weeks was experienced as too short for long-lasting change.