Leganés was relegated from La Liga in 2019–20 along with Espanyol and Mallorca.
The three clubs occupied the bottom three places when the season ended: Leganés finished 18th with 36 points, Mallorca finished 19th with 33, and Espanyol finished last with 25. Leganés were separated from safety by only one point, making their relegation especially painful.
The campaign was disrupted by the COVID-19 pandemic, with Spanish league matches suspended in March 2020 before resuming behind closed doors in June. Leganés were finally relegated after drawing 2–2 with Real Madrid on the last day, a result that left them below Celta Vigo.
The season had begun with Mallorca newly promoted, while Espanyol had been a long-standing top-flight club. Leganés had spent four consecutive seasons in La Liga, so their drop ended the longest top-division run in the club’s history at that time. Alavés and Eibar avoided relegation.