This case study describes a mixed methods study evaluating a short message service information campaign with signing Deaf South Africans through pre- and post-surveys and focus groups. A mixed methods study refers to a study that uses both quantitative and qualitative methods. This case provides the rationale for choosing a mixed methods design and outlines the advantages of this design to explore both the effectiveness and acceptability of the SMS campaign intervention. This study also discusses the challenges when working with hard-to-reach populations such as the Deaf. It demonstrates how sampling challenges influenced the choice of the quantitative component and explains why we opted for a pre- and post-survey design rather than a randomized controlled trial.