Although international volunteer service is growing in prevalence worldwide, there is little rigorous research about its impacts. This quasi-experimental study assesses the perceived impacts of international service on international volunteers. We focus on four internationally oriented outcome categories: international awareness, intercultural relations, international social capital, and international career intentions. International service provides exposure and immersion to develop these perspectives, relationships, and intentions. Using generalized linear mixed regression modeling, international volunteers (n = 145) are statistically more likely to report increases between the baseline (1 month before service) and postservice time periods (1 week to 1 month after service) in all outcomes except intercultural relations, as compared to a matched comparison group (n = 145). Age, race, occupational experience, and previous international experience are also associated with various outcomes. Implications include continued cultural growth, potential mutual impacts of international social capital, and future research on the volunteers and host communities.