This study investigates the influence of digital marketing on membership retention intention among fitness club members in Ho Chi Minh City, Vietnam. A quantitative research approach was adopted to examine the relationships among Digital Marketing (DM), Customer Experience (CX), Brand Engagement (BE), and Membership Retention Intention (MRI). For manuscript-development purposes, an illustrative dataset of 428 fitness club members was used to demonstrate the proposed analytical model. Data were analyzed using SPSS and SmartPLS. The illustrative results indicate that digital marketing positively influences customer experience and brand engagement. Customer experience also has a significant positive effect on brand engagement and membership retention intention, while brand engagement emerges as the strongest direct predictor of retention intention. Furthermore, customer experience and brand engagement sequentially mediate the relationship between digital marketing and membership retention intention. The illustrative model explains 60.3% of the variance in membership retention intention. The study contributes to sport marketing and fitness management literature by demonstrating that digital marketing promotes membership retention not merely through promotional exposure but through the creation of positive customer experiences and deeper brand engagement. The findings suggest that fitness clubs should develop personalized, interactive, and relationship-oriented digital marketing strategies to enhance member retention and long-term business sustainability.