This paper analyses whether low-skilled workers' training participation and task flexibility contribute to their firm-internal and firm-external mobility, and find that both training participation and task flexibility contribute only to firm-internal employability. However, the workers' participation in training plays a much more explicit role in their firm-internal career than their task flexibility does, as the former appears to be an important means to increase their opportunities in the firm-internal labour market. Neither the low-skilled workers' participation in training nor their task flexibility contributes to their external employability. Task-flexible, low-skilled workers are less likely to expect to be externally employable than non-task flexible workers are. The focus of the low-skilled workers on their firm-internal employability can be explained by the fact that such workers usually have more opportunities to improve their position in the firm-internal labour market than in the external labour market.