Abstract Background and aims Heated tobacco products (HTPs) are increasingly used by individuals attempting to quit smoking, particularly in Japan where HTP use is prevalent; however, the effectiveness of HTPs in achieving complete tobacco abstinence remains unclear. This study aimed to estimate the likelihood of complete tobacco abstinence and combustible cigarette abstinence among exclusive HTP users and dual users compared with exclusive combustible cigarette users. Design A prospective cohort design using sequential annual follow‐ups (2019–2023) from the Japan ‘Society and New Tobacco’ Internet Survey (JASTIS). Inverse probability‐weighted Poisson generalized estimating equation models were used to estimate rate ratios for abstinence outcomes. Setting Nationwide internet‐based survey conducted in Japan. Participants A total of 8969 Japanese adults aged 20 years and older who were current tobacco users at baseline were included. Participants were categorized as exclusive combustible cigarette users (55.6%), exclusive HTP users (16.3%) or dual users (28.0%). Exclusive HTP users were further categorized as established (daily use, ≥100 HTPs used, or >12 months of lifetime use) or non‐established users. Measurements Primary outcomes were (1) complete tobacco abstinence—defined as no current use of any tobacco products used at baseline—and (2) combustible cigarette abstinence after one year. Abstinence required selecting “used regularly in the past but quit” for each relevant product. Findings Compared with exclusive combustible cigarette users (as classified at baseline), the rate ratio (RR) for complete tobacco abstinence was 0.85 [95% confidence interval (CI) = 0.71–1.02] among exclusive HTP users and 0.49 (95% CI = 0.42–0.58) among dual users. When stratified, established HTP users had a statistically significantly lower likelihood of complete tobacco abstinence (RR = 0.57, 95% CI = 0.47–0.70), while non‐established users showed a higher likelihood (RR = 2.41, 95% CI = 1.83–3.17). Compared with exclusive combustible cigarette users, the RR for combustible cigarette abstinence after one year was 0.93 (95% CI = 0.83–1.04) among dual users. Conclusions In this one‐year follow‐up, dual use of cigarettes and heated tobacco products (HTP) and established exclusive HTP use were associated with lower rates of complete tobacco abstinence compared with exclusive cigarette use, while non‐established exclusive HTP use showed higher abstinence rates. Overall, HTP use was not associated with higher tobacco abstinence rates.