There were massive interruptions, including patient visits for dietary advice and dental services, during the COVID-19 outbreak. This study assessed the feasibility of an online diabetes wellness programme among periodontitis patients with type II diabetes mellitus. Patients were grouped into the intervention group (IG) and control group (CG). At baseline and week 12, all patients answered online questionnaires on diabetes-related knowledge, physical activity, and oral impacts on daily performances (OIDP). Body weight and waist circumference were self-measured with guided instructions. Diet recalls were used to estimate dietary and added sugar intake. All patients received a weekly educational video, but the IG attended three e-consultation sessions with a dietitian (weeks 1, 3, and 8) and a dentist (week 8) via video call. A semi-structured interview was conducted to collate qualitative feedback among the IG participants at the end of the programme. A total of 24 periodontitis patients (14 IG and 10 CG) participated in this study. Among the IG patients, significant improvements in diabetes knowledge, body weight, BMI, calories, carbohydrates, fat, and added sugar intakes were observed at week 12. The CG patients only had a significant reduction in carbohydrate intake post intervention. No changes were reported in physical activity level and OIDP for both groups. Feedback received from the IG participants included convenience, practical, preferred approach during the pandemic, increased awareness and knowledge, and favourable lifestyle changes. This study demonstrates that an online diabetes wellness programme with healthcare professionals is feasible and can facilitate knowledge and lifestyle improvements that can be adapted during the crisis situation.