While multicultural teaching strategies show promise in meeting the educational needs of ethnically, culturally, and linguistically diverse students, science teachers often leave traditional preparation programs with little-to-no exposure to such practices. As there are few resources around multicultural science education, teachers must develop a strong "pedagogical design capacity"--the ability to appropriately identify and mobilize curricular and personal resources--for constructing multicultural curricula for their students. This explanatory case study describes the curriculum design processes of beginning in-service secondary science teachers as they redesigned their own curriculum units with stronger multicultural science connections than originally present. Primary data sources included teachers' original and final science curriculum units and daily curriculum-writing reflections. Data were analyzed using mixed methods, including deductive coding based on James Banks' typologies of multicultural content integration. Results indicate that the increase in multicultural content integration from teachers' original to final science units was significant. Thematic analysis revealed four "design moves" made by the teachers: (1) Creating student-centered instruction from student input, (2) Increasing opportunities for collaboration, (3) Integrating cultural and community sources of knowledge, and (4) Situating science lessons within sociopolitical contexts. The number of design moves made and resources utilized were positively associated with the multicultural connections present in teachers' final curricula. Implications are provided to support teachers in designing multicultural science experiences.