Background and aims COVID-19 is likely to affect the lives of individuals with type 2 diabetes. However, the effect of COVID-19 lockdown on physical activity and glycemic control in such individuals is not known. We studied the physical activity and glycemic control during lockdown in comparison to pre-lockdown parameters in individuals with long-standing type 2 diabetes. Methods This prospective, observational study includes 2240 people with T2DM regularly attending diabetes clinic prior to lockdown. Glycemic record, HbA1c, and physical activity assessed with Global Physical Activity Questionnaire (GPAQ) as metabolic equivalents (MetS min/week) were obtained during lockdown (minimum duration of 3 months). Results A total of 422 out of 750 participants (nest) responded. The median (IQR) for age was 58 (52 to 64) years, duration of diabetes 11 (6 to 16) years, prevalent foot complications in 59.7%, and atherosclerotic cardiovascular disease in 21.3% of participants. There was a decrease in HbA1c from 7.8% (6.9 to 9.4) prior lockdown to 7.4% (6.6 to8.7) during lockdown [ΔHbA1c − 0.41 ± 0.27% (p = 0.005)] and postprandial blood glucose 200.0 mg/dl (152.0 to 252.0) to 158.0 (140.0 to 200.0) mg/dl (p < 0.001). The physical activity increased during lockdown from a GPAQ score 140 (0.0 to 1260) MetS to 840 (0.0 to 1680) MetS (p = 0.014). The improvement of glycemic control was observed in either gender and independent of the presence of foot complications or increase in physical activity. Conclusions There is an overall improvement of glycemic control during COVID-19 lockdown independent of increase in physical activity in people with long duration of diabetes.