All over the world, educational science outreach programs in which students can perform laboratory work have been developed. A common goal of these programs is to counteract students' decreasing motivation in STEM education. In Germany, several outreach science labs have been established over the last 20 years. It is assumed that the characteristics of these labs foster students' basic need satisfaction and qualities of motivation such as intrinsic motivation and flow. However, research in this field often lacks comparisons of motivation between the learning environments "outreach science lab and school." Thus, the current study investigated students' perceived need satisfaction (relatedness, competence, and autonomy), intrinsic motivation, and flow experience during experimentation at an outreach science lab (n = 231) and at school (n = 203). We found that experimentation in the two different learning environments resulted in a comparable degree of perceived autonomy and intrinsic motivation. However, differences in perceived relatedness, competence, and flow experience were found in favor of the students who experimented at the lab. Thus, visiting outreach science labs is especially beneficial for students' perception of relatedness, effectiveness, and enjoyment during experimentation.