Cambodia is a major sending country of migrant workers to booming Asian economies, including Malaysia, the Republic of Korea and neighbouring Thailand. From 1998 to 2007, 8,969 documented migrants worked in Malaysia, 7,042 of them women. An estimated 10,000, regular and irregular Cambodian migrants worked in Malaysia in 2003, and 2,464 Cambodian migrants currently work in the Republic of Korea. In 2002-2003, remittances to Cambodia amounted to approximately USD 3,177,600.

Documented migrant workers to Malaysia and the Republic of Korea receive a three month pre-departure vocational training course from recruitment agencies that focuses on reproductive health, HIV/AIDS and general medical exams. There are no evaluation and monitoring processes to ensure the delivery of such training courses and to assess their quality. Undocumented migrant workers, who are especially exposed to exploitative forms of labour in their destination countries, are difficult to reach with information on HIV-risk situations and safe migration.

In 2005, 181,579 Cambodians were registered with the Thailand Ministry of Interior, 123,998 male and 57,581 female, representing approximately 13% of all registered migrants in Thailand but this figure decreased to an estimated 37,142 by 2006 as few new work permits are being issued. It is estimated that there are another 180,000 undocumented migrants. Male migrant workers tend to stay short term in Thailand, while female migrant workers usually stay longer.

Undocumented migration from Cambodia to Thailand is an increasing concern. Documented migrant workers in Thailand have limited access to health care and treatment services due to language and cultural barriers. Undocumented migrants, who are less visible and thus more difficult to reach by non-profit organizations, remain largely isolated from HIV prevention, care and treatment services. Poor living conditions and discrimination are just some of the difficulties Cambodian migrants face.

Cambodia is a destination country for labour migrants, mainly from Viet Nam and China. The sex industry employs Vietnamese female migrants, who are quite vulnerable to HIV due to their profession and irregular status. The country has also been a major host for Vietnamese asylum seekers and refugees.

Cambodia is a source and transit country for men, women, and children trafficked for commercial sexual exploitation and forced labour to Thailand and Malaysia; it is also a transit and destination country for Vietnamese and Chinese women and children for sexual exploitation.

There is a lack of comprehensive information on HIV infection rates and risk behaviours among mobile populations.