To support teachers in enhancing ocean literacy, the Center for Microbial Oceanography: Research and Education (C-MORE) has developed a series of portable, hands-on science kits on selected topics in oceanography. This paper provides an overview of kit content, describes how the kits were developed, and evaluates their efficacy as a curriculum supplement in formal classroom environments by using two studies, a qualitative assessment of teacher experience and a quantitative assessment of student learning. The teacher surveys (n = 45) indicate the kits were used in a wide range of class types and grade levels, describe the kits as useful classroom tools that actively engaged students and resulted in meaningful learning, and strongly indicate that the teachers plan to continue to use the kits in the future. The student learning assessment (n = 1,236) employed a pretest, posttest 1, and posttest 2 methodology. The pretest and posttest 1 were given immediately before and after instruction, respectively; posttest 2 was given at least 2 weeks after instruction. Engaging with the science kits resulted in significant knowledge acquisition (pretest-posttest 1 mean differences of 0.21-0.41) and retention (pretest-posttest 2 mean differences of 0.18 to 0.39), with significance defined at the a = 0.05 level. In the 2 weeks after kit instruction, all kits showed a slight, nonsignificant loss in knowledge (mean differences of -0.01 to -0.04). Together, the teacher and student evaluations indicate that the C-MORE kits are effective classroom tools that can serve as a model for hands-on curriculum supplements.