The great waves and the surfers that dare to ride them have made Puerto Escondido a place that depends on the sea. It was a town of fishermen that has transformed into the mecca of surfing in Mexico, into a city and tourist destination, all thanks to its beautiful beaches, impressive sunsets, and large waves. Today, Puerto Escondido is home to people from different corners of Oaxaca and Mexico. People that have arrived for different reasons, but that depend directly or indirectly from the sea. Some of them found in the Guardarenas project an opportunity to contribute to the conservation of the beaches through environmental education, involving children in citizen science activities, science in action. This initiative, a proposition by the United Nations, has been replicated around the whole world, but in our country, is found only in Puerto Escondido. The short movie Guardarenas is a window to coast full of Oaxacan children, young people, and adults that collaborate today for the future. With a bit of training, a scientific team and lots of passion, the Guardarenas monitor different variables of the beach once a month, all while having fun and pretending to be scientists. In this video, we accompany them for monitoring activity, and they tell us about what’s in between the lines, showing us that conservation is a social, solitary, and empathetic processes with ecological purposes.