Production processes are often organised in teams, yet there is limited evidence on whether and how social connections and financial incentives affect productivity in tasks that require coordination among workers. We simulate assembly line production in a lab-in-the-field experiment in which workers exert real effort in a minimum-effort game in teams whose members are either socially connected or unconnected and are paid according to the group output. We find that group output increases by 15% and wasted individual output is lower by 30% when workers are socially connected with their co-workers. Unlike the findings of existing research, increasing the power of group-based financial incentives does not reduce the positive effect of social connections. Our results are driven by men whose average productivity is significantly lower than that of women. These findings can be explained by pro-social behavior of workers in socially connected teams.