A glider is an autonomous underwater vehicle equipped with oceanographic and biogeochemical sensors that travels through the ocean collecting data and transmitting them to shore via satellite. Thanks to its low energy consumption, it can cover thousands of kilometers over several weeks autonomously, while being remotely supervised from land. Once a mission has been programmed, the glider is deployed at sea, where it moves in a dives (yo-yo) pattern from the surface down to depths of up to 1,000 meters, collecting physical and biogeochemical observations of the ocean. At regular intervals, it surfaces to transmit its position and data via satellite. At the end of the mission, the glider is recovered at its last reported position. The gliders are named Jimena and Juan. Jimena pays tribute to Jimena Quirós, the first Spanish oceanographer, who was already studying the waters off Santander in 1932. Juan honors Juan de Santander, also known as Juan de Cueto, one of the few sailors who survived the first circumnavigation of the globe led by Ferdinand Magellan and Juan Sebastián Elcano.