This article introduces the Collaborative Online Learning Across Borders (COLAB) teaching and research program. It outlines the development of the cross-national collaboration, and examines the learning in four teacher education programs in New Zealand and the United States of America. COLAB aims to support teacher candidates, in the US and abroad, to begin their teaching career with insights into the complexities of working with people from diverse social and cultural contexts. This article presents a research study that examined the online intercultural interactions and understandings among undergraduate and graduate preservice (and some inservice) teachers (n = 110) across four universities during a 4-week unit. It details the online teaching techniques involved in COLAB and highlights the development of intercultural understandings through an online learning experience among the preservice teachers. The preservice teachers' insights and sensitivities to the other, ethnocentrism, and the online learning space are theorized through a framework of cultural otherness and interculturality, which emphasizes the unique potential for cross-cultural experiences in this online format.