Assistive technologies, such as robots, have proven to be useful in a social context and to improve the quality of life for people with dementia (PwD). This study aims to show how the engagement between two social robots and PwD in Australian residential care facilities can improve care quality. An observational method is adopted in the research methodology to discover behavioural patterns during interactions between the robots and PwD. This observational study has undertaken to explore the improvement arising from: (1) approaching social baby-face robots (AR), (2) experiencing pleasure engaging with the robots (P), (3) interacting with the robots (IR), and (4) interacting with others (IO). The findings show that social robots can improve diversion therapy service value to PwD through sensory enrichment, positive social engagement, and entertainment. More than 11,635 behavioral reactions, such as facial expressions and gestures, from 139 PwD over 5 years were coded, in order to identify the engagement effectiveness between PwD and two social robots named Sophie and Jack. The results suggest that these innovative social robots can improve the quality of care for people suffering from dementia.