In the pursuit of promoting diversity, equity, and inclusion (DEI) in the field of Astrophysics and High Energy Physics, a group of young researchers at ICCUB, under the scope of the DEI-ICCUB commission, has built a successful mentoring program for master’s students in Astrophysics, Particle Physics and Cosmology at the University of Barcelona. This initiative aims to support and guide aspiring scientists through their academic journey and beyond, while keeping a focus on individuals from minority groups. The program started in 2020, during the pandemic, and initially targeted only female master’s students. In 2021, a group of PhD students formalized the program, now targeting two groups: students who belong to minority groups in academia (minority group), and a general group including all master students interested in the program. The objectives of the mentoring program are to facilitate the engagement of master’s students with researchers across various academic levels, with a different focus depending on the group. For the minority group, they also include creating a supportive and safe space for sharing experience among young female researchers, and addressing the challenges faced by female students in STEM. For the general group, they encompass cultivating interest in academic careers, offering guidance with the master’s program and throughout PhD application processes. The outcomes of our program have been positive and encouraging, with students reporting increased motivation, a sense of belonging, and tangible academic progression. Moreover, our efforts have contributed to retaining talented individuals within our institute, further enriching our scientific community. As we reflect on our achievements, we also acknowledge the need for continuous improvement and expansion of our DEI efforts. In this talk we review the consequent impact and challenges of this project, which has relied entirely on the selfless commitment of a few PhD students.