One challenge of collecting socioeconomic data, such as data on time use, is recall biases. While time-use researchers have continuously developed new methods to make data collection more accurate and easy, these methods are difficult to use in developing countries, where study participants may have low literacy levels and no “clock”-based concepts of time. To contribute to the closing of this research gap, we developed a picture-based smartphone app called “Time-Tracker” that allows data recording in real time to avoid recall biases. We pilot tested the app in rural Zambia, collecting 2790 data days. In this paper, we compare the data recorded with the app to data collected with 24-hours recall questions. The results confirm the literature on recall biases, suggesting that using the app leads to valid results. We conclude that smartphone apps using visual tools provide new opportunities for researchers collecting socioeconomic data in developing countries.