Background: Vaccination against seasonal influenza (SIV) is recommended for patients with diabetes, but their vaccination coverage is unsatisfactory in France and elsewhere. This qualitative survey of people with diabetes sought to explore 1) the extent to which SIV-related behaviour is more or less automatic; 2) reasons they choose/reject SIV; 3) their trust/distrust in authorities, science, and medicine. Methods: We conducted semi-structured in-depth interviews of 19 adults with diabetes in 2014. We recruited them through physicians or patient associations and implemented an analysis of thematic content. Results: Eight patients were vaccinated against flu in the preceding flu season and 11 were not. SIV uptake and refusal were stable over time and justified by multiple arguments. Coupons for free vaccines and regular doctor visits contributed to the habit of vaccination. Vaccination decisions were frequently anchored in past experiences of influenza and its vaccine. Patients often justified non-vaccination with attitudes of trivialisation/relativisation of influenza-associated risks and the perception that these can be controlled by means other than vaccination (e.g., through the avoidance of exposure). Some misbeliefs (e.g., SIV causes influenza) and doubts about SIV effectiveness and safety also existed. Several patients reported increased mistrust of SIV since the A/H1N1 pandemic in 2009. Patients trusted their doctors strongly regardless of their SIV behaviour, but unvaccinated patients had little trust in the government and pharmaceutical companies. Some discordances were found between perceptions and behaviour (e.g., remaining vaccinated despite doubts about SIV effectiveness or remaining unvaccinated despite feelings of vulnerability towards influenza complication), suggesting the existence of some vaccine hesitancy among patients. Conclusion: This study among patients with diabetes suggest that SIV uptake is stable, thanks to a favourable environment. Nonetheless, SIV refusal is also stable over time. Unvaccinated patients used multiple arguments to justify SIV refusal, including compensatory health beliefs. Physicians should take every opportunity to recommend SIV. The necessary individualised patient education regarding SIV requires better physician training in patients priorities. While almost all patients strongly trust their doctors, unvaccinated patients distrust distal stakeholders: it is absolutely essential to restore trust in them and to develop new more effective influenza vaccines.