The 2020 Santé publique France Health Barometer for Saint-Pierre-et-Miquelon includes individuals aged 18 to 85 who have been residing in Saint-Pierre-et-Miquelon for at least six months and who speak French. Nine hundred ninety-two people responded to the questionnaire, for a response rate of 63.8%. The prevalence of current smoking among 18- to 75-year-olds is 43.2% among men (vs. 33.0% in mainland France) and 35.3% among women (vs. 24.6%). This smoking prevalence—particularly daily smoking—is significantly higher than in mainland France among men and women in the 18–54 age group. The rate of people who have had at least one episode of heavy episodic drinking (HED) in the past year stands at 46.6% (vs. 35.2% in mainland France), with the highest rates among those aged 18–24 (84.6%) and 25–34 (74.9%). Among 18- to 24-year-olds, 26.3% (vs. 13.4%) reported at least ten episodes of heavy drinking (API) in the past year; this figure is 23.6% among 25- to 34-year-olds (vs. 9.0%). Mental health issues are significant among young people in Saint-Pierre-et-Miquelon, as 25.6% (vs. 11.7% in mainland France) of 18-24-year-olds reported at least one major depressive episode (MDE) in the year preceding the survey, and 19.2% (vs. 4.6%) reported having had suicidal thoughts during that period. Over the course of their lives, 11.8% (vs. 6.1%) of 18- to 24-year-olds have made at least one suicide attempt. The prevalence of diabetes (8.8% among men vs. 7.9% in mainland France, and 8.0% among women vs. 3.7%) and of overweight/obesity (15.3% obesity among men vs. 13.2% in mainland France, and 17.7% among women vs. 13.8%) are also high in Saint-Pierre-et-Miquelon, particularly among people aged 55 and older, for whom prevalence rates are significantly higher than those in mainland France.