To encourage Hispanic participation and enrollment in the geosciences and ultimately enhance diversity within the discipline, we recruited ten middle and high school science teachers for a three-week field experience to the Central Mexico volcanic belt. Supported by the National Science Foundation’s Opportunities for Enhancing Diversity in the Geosciences (OEDG) program, the experience began with a mini-pedagogy course on multiculturalism and inquiry methodologies at Northern Illinois University (NIU) and continued with fieldwork in Mexico, where participants worked with Universidad National Autonoma de Mexico geoscientists, visited local schools, and attended cultural events. The experience culminated in the teachers producing standards-based educational materials from their field experiences and presenting them at professional conferences. We measured the efficacy of these activities quantitatively via pre- and post-tests to assess affective domain changes (i.e., confidence levels, preconceptions, and biases), NIU staff observations of participants in their home institutions, and evaluations of participants’ field books and pedagogical materials. Additionally, effectiveness was measured by reviews of still and video footage, and examination of comments in field books and on surveys given before the program, directly after, and one year after the experience. We present these data here and identify specific activities that are both effective and efficient in changing teacher behaviors and attitudes, enabling them to better connect with their Hispanic students in their geoscience classrooms.