Research on collective decision-making has shown that groups can outperform their best individual members through “confidence sharing”: individuals verbally communicate how confident they feel in their individual judgements so as to arrive at a collective decision. However, such explicit communication of confidence estimates may not always be possible. Thus, in the present study, we investigate an alternative, implicit way of confidence sharing. We test the hypothesis that, in the absence of verbal communication, two individuals can infer each other’s subjective confidence through simple action observation, and in this way achieve a group benefit. To this end, we ask two participants (A and B) to solve a 2AFC perceptual task, with individual decisions followed by a collective decision. Participants express their decisions by aiming for one of two targets, while movement kinematics are recorded. In each trial, participant A (B) aims for one of the two targets, then observes participant B (A) also aiming for one of the two targets, and then makes the collective decision. Our results show that participants perform better collectively, and that they read out confidence from each other’s movements and incorporate this inferred confidence in the collective decision-making process.