Motorcyclist safety is a major concern in many developing countries. Understanding motorcycle riders' risky behaviours, particularly among the younger population, is essential to developing effective interventions. This paper explores the correlations between mobile phone use while riding and other risky riding behaviours as well as the relationships between perceived risks and risky riding behaviours, using an online survey of university students in Vietnam. Results show that calling while riding a motorcycle had the highest prevalence (74%) while reckless overtaking had the lowest prevalence (33.2%). Survey participants who indicated that they had the behaviours of reckless overtaking or riding on sidewalks were around twice as likely to call, text, or search for information while riding. In addition, those who admitted that they rode a motorcycle while under the influence of alcohol were nearly twice as likely to call or text while riding. The results also show that perceived crash risks reduced the likelihood of risky riding behaviours, including calling, texting, searching for information, speeding, running red lights, riding on the wrong side of a road, and riding on sidewalks. A more coordinated approach to enforcement is needed to help reduce the prevalence of multiple risk taking behaviours among motorcyclists.