Using continuous pulse oximetry (cSpO2) to monitor children with bronchiolitis who are not receiving supplemental oxygen is a form of medical overuse. In this longitudinal analysis from the Eliminating Monitor Overuse (EMO) study, we aimed to assess changes in cSpO2 overuse before, during, and after intensive cSpO2‐deimplementation efforts in six hospitals. Monitoring data were collected during three phases: “P1” baseline, “P2” active deimplementation (all sites engaged in education and audit and feedback strategies), and “P3” sustainment (a new baseline measured after strategies were withdrawn). Two thousand and fifty‐three observations were analyzed. We found that each hospital experienced reductions during active deimplementation (P2), with overall adjusted cSpO2 overuse decreasing from 53%, 95% confidence interval (CI): (49–57) to 22%, 95% CI: (19–25) between P1 and P2. However, following the withdrawal of deimplementation strategies, overuse rebounded in all six sites, with overall adjusted cSpO2 overuse increasing to 37%, 95% CI: (33–41) in P3.