This paper articulates and illustrates design principles that guided the development of a set of hands-on teaching activities for the national science and mathematics curricula at junior-high and high-school level education in Timor-Leste, a small, low-income nation in Southeast Asia. A partnership between a university, an international science educator (the first author), local teachers and students engaged in a series of collaboratively created activities to make a set of learning resources to support student learning, teacher development, and subsequent curriculum development. The design principles included: seeking locally-rooted topics, supporting experiential learning, and ensuring sustainable use and delivery of instructional materials. These design principles guide the enactment of instructional practices to support culturally relevant learning situated in problems of everyday life. Using three examples of design activities that emerged from Timor-Leste's culture and environment, we demonstrate the high utility that these design principles have in sustaining further education and development in Timor-Leste, as well as creating and supporting inquiry-driven learning environments more generally. (Contains 1 table, 4 figures, and 3 footnotes.)