Postprandial hyperglycaemic (PPH) episodes are a challenge to diabetes management, yet limited research exists on how people with diabetes experience PPH episodes. The study investigated how people with diabetes taking mealtime bolus insulin experience PPH episodes: causes, contributing situations and corrective actions. Results from a web survey of 906 adults with type 1 or 2 diabetes taking self-administered bolus insulin in the US, UK and Germany showed that 66% of respondents found it difficult to stabilise their blood glucose (BG) levels after eating in the past week. Respondents experiencing inadequate PPG control in the last week experienced 1.7 PPH episodes on average. The most common reasons given for the most recent incident of PPH were eating food containing more fat/sugar than estimated (31%) and eating more food than calculated dose for (30%). Respondents indicated that the most common situations contributing to their most recent PPH episode were stress (27%), eating at a restaurant (25%), being busy (21%) and feeling tired (19%). In terms of corrective actions, 71% of respondents took an additional dose of bolus insulin, 12% waited and took bolus when they next ate and 5% skipped their next meal/snack. These findings demonstrate PPH episodes are prevalent and highlight the challenge in calculating and taking mealtime bolus insulin. Additional bolus dosing to correct for PPH episodes may be an obstacle to optimal diabetes management and has economic implications for overall treatment costs. The findings suggest improving diabetes management, education and treatment for people taking mealtime bolus insulin is warranted.