Sex workers are highly mobile populations, moving both within and accross national boundaries, as either documented or undocumented labour. However, labour laws rarely, if ever, offer protection and benefits to local or migrant sex workers. Migration and mobility factors that can significantly increase the vulnerability of sex workers to HIV and sexually transmitted infections, in large part due to their undocumented status including lack of work permits, poor working conditions in some cases, lack of access to health care, occupational health and safety standards, and other forms of labour protection.