This study investigates the relationship between external mobility and career advancement among employees of Coca-Cola Nigeria and Nestlé Nigeria; the study further examined the relationship between inter-organizational movement and promotion opportunities. Using a survey design, data were collected from 92 respondents and analysed with STATA software. Descriptive statistics highlighted that 76% of employees agreed inter-organizational movement improved promotion opportunities. Correlation analysis provided deeper insights: inter-organizational movement was strongly and positively correlated with promotion opportunities (r = 0.62, p < 0.01), while external mobility showed a significant relationship with career advancement (r = 0.58, p < 0.05). These results indicate that employees perceive mobility between firms as a viable pathway to faster promotions, skill enhancement, and improved compensation. However, the findings also reveal organizational challenges, particularly for Coca-Cola Nigeria, which faces knowledge drain and increased recruitment costs. Conversely, Nestlé benefits from the inflow of experienced professionals. The study concludes that external mobility significantly accelerates career advancement but creates retention challenges, necessitating balanced strategies for sustainable workforce management.