Abstract Background We examined changes in diabetes care and management practices before and during the COVID-19 pandemic. Methods Population-based data regarding four diabetes-related healthcare engagement and four self-management indicators were obtained from adults with diabetes surveyed in 19 US States and Washington DC through the Behavioral Risk Factor Surveillance System. Using logistic regression, we estimated changes in the prevalence of each indicator, overall and by sociodemographic subgroups in 2019 (before the pandemic) and 2021 (during the pandemic). Results Between 2019 and 2021, the prevalence of biannual HbA1c tests reduced by 2.6 percentage points (pp; 95% confidence interval: −4.8, −0.4), from 75.4% to 73.1%, and prevalence of annual eye exams fell by 4.0 pp (−6.2, −2.8), from 72.2% to 68.7%. The composite indicator of engagement with healthcare for diabetes control fell by 3.5 pp (−5.9, −1.1), from 44.9% to 41.9%. Of self-management behaviors, avoidance of smoking increased by 2.0 pp (0.4, 3.6) from 84.7% to 87.1%. Conclusions The findings suggest a deterioration of the uptake of evidence-based, preventive health services requiring laboratory services and clinical examination for diabetes control during the pandemic. On the other hand, smoking rates decreased, suggesting potential positive impacts of the pandemic on health behaviors in people with diabetes.