Despite the need for evidence-based practice for children with autism spectrum disorders in the community, especially in areas with a scarcity of qualified experts and high financial costs, there is a lack of evidence concerning the potential benefits of early interventions which may be affordable in the real world (e.g. low-intensity behavioral or eclectic interventions). This study examined behavioral changes in preschool-aged children with autism spectrum disorders who received low-intensity behavioral interventions (a mean of 5.5 h per week) or non-behavioral eclectic interventions delivered in community settings in Japan across a 1-year period and compared outcomes between the groups. We assessed children’s developmental quotient, adaptive behavior, autism symptom/severity, and maternal stress and depression at baseline and after 1 year. Our results revealed that children receiving interventions in their communities showed improvement in language and social development. Further, the degree of improvement in children receiving low-intensity behavioral interventions was significantly greater than in children receiving non-behavioral eclectic interventions. The improvement was associated with the intensity of total, especially one-to-one interventions. On the other hand, there were no group differences in the degree of improvement in other outcome measures. Our results suggest that some preschool-aged children with autism spectrum disorder may benefit from low-intensity behavioral interventions for their language and social development. A greater intensity of one-to-one interventions was found to be associated with greater progress in language development and communication skills. The current study highlights the importance of implementing early interventions in the community, even at a low intensity.