Recent research has shown that individuals tend to have higher pain tolerance after participating in a vigorous activity in synchrony with others compared to after they perform the same activity alone. The current study was designed to examine if the effect of this behavioral synchrony differs according to the social presence of teammates or strangers. Twenty-four individuals rowed on ergometers for 45 min in both individual and group conditions. Half the participants rowed in the group condition with teammates, whereas the other half rowed them with confederates. ANOVA procedures revealed pain tolerance was significantly higher after participating in a group condition than in an individual condition, and that there was no significant difference between a group of strangers and teammates. This higher pain tolerance has been inferred as an indicator of endorphin activity, which may be related to behavioral synchrony.