OpenStreetMap (OSM) is an openly-licensed geospatial database created and edited by millions of volunteers worldwide. This database is used in various humanitarian projects, such as mapping during disaster relief operations or malaria elimination campaigns. In some parts of the world, for example certain areas in Mozambique, no official cartographic data is available and hence OSM can play a crucial role. A mapathon (literally “map marathon”) is a collaborative effect that is an effective method of collecting map data in unmapped areas. Through the YouthMappers global initiative (http://www.youthmappers.org), students are actively engaging in OSM-based collaborative mapping efforts internationally. We will briefly discuss the process followed by three YouthMappers chapters; Politecnico di Milano (Italy), Texas Tech University (United States of America), and University of Pretoria (South Africa), and lessons learned. In Milano, students’ mapathons are organized monthly and they are focused either on field-mapping (e.g. to improve the OSM map of the university) or remote mapping on humanitarian tasks; learning sessions on OSM editing tools are also held periodically. In Texas, students organize mapathons several times per year, and they can take a dedicated service-learning course for credit where they work on teams with other students around the world to map the same areas and research the humanitarian or development issue affecting the region. In Pretoria, monthly mapathons are held and each mapathon focusses on a different area. Extra credits are offered to encourage participation. From our experiences, it became evident that even though OSM tools are user-friendly, students do need some training, and a short training video as part of the introduction presentation was developed. Additionally, understanding the purpose for a mapathon in an area, motivates and encourage active participation and ensures that quality data is captured. Internationally students participate and learn from other YouthMappers chapters through regular organized web conferences. In conclusion, incorporating mapathons into the curriculum encourages students to contribute needed data required for humanitarian projects. Simultaneously, students get practical experience in data capturing and awareness is raised of humanitarian challenges in other parts of the world.