The Bangsaen 42 Chonburi Marathon is the most attended full-marathon event in Thailand and a high-standard running event classified as the World Athletics Elite Label Road Race. The increase in runners reflected the response from both regular and new runners. This mixed methods study aimed to analyze branding processes, marketing communication perceptions, brand personality, and the relationships between perceptions of marketing communication and brand personality. The qualitative approach involved in-depth interviews with three key informants. A quantitative approach was applied to the questionnaire. The sample included 400 runners who participated in this event using nonprobability sampling. Data were analyzed using descriptive statistics and Pearson’s correlation statistics, with a significance level of 0.05. The results showed three brand-building processes: 1) strategic brand analysis of runners’ needs, organizing marathon running events in Thailand, and self-analysis; 2) brand identity system under the only marathon running event in Thailand with world-class standards under the concept of “The passion of world-class marathon” and brand value of “You will run a full marathon with world-class standard;” 3) brand identity implementation systems through various media to demonstrate sound management. This sample group perceived marketing communication at a moderate level, and the perceptions of brand personality of the marathon met the competence the most. The relationships between marketing communication and perceptions of sincerity were positively correlated, with a correlation coefficient of 0.46 and a statistical significance of 0.05. AcknowledgmentA research grant from the Faculty of Sport Science, Burapha University supports this study.