Diabetes is a major health and social cost in New Zealand, particularly for Pacific peoples. We intend to develop a text message programme that will motivate and support healthy behaviour change in Tongan people with pre-diabetes in order to prevent the onset of diabetes. This will build on SMS4BG - a text message self-management support programme for those with poorly controlled diabetes. It will also build on international diabetes prevention programmes which have been successful at preventing diabetes but are costly and resource intensive. We will work with Tongan community groups to ensure the programme is appropriate. The trial will test the effectiveness of the programme by comparing levels of long-term glucose control (HbA1c) in those receiving the programme and those who do not. If the programme is successful at improving glucose control it would be easily scalable and distributable across the country.