Founded in 1920 in the Navarrese capital of Pamplona. "Osasuna" means "health" or "strength" in Basque. Despite oscillating between divisions, the club remains deeply beloved in Pamplona. As a member-owned club, they have consistently rejected offers from private investors, embodying a community-first philosophy.

El Sadar's atmosphere is among the most intense in La Liga. The 23,516-capacity ground is almost always full and is regarded as one of the toughest away trips in Spanish football.

Following Vicente Moreno's departure, Alessio Lisci was appointed in summer 2025. The 39-year-old Italian earned his reputation by guiding Mirandes to strong results in Spain's second tier — an unusual pathway that underlines his tactical acumen.