The first Vietnamese settlers in Cambodia were rice farmers, many of whose ancestors migrated across disputed borders as long ago as the late seventeenth century; over generations they moved north along the Mekong and today mostly farm in the southeast provinces. The educated, predominantly Christian Vietnamese population of Phnom Penh has its origins in the civil servants brought over during Vietnamese rule and the French protectorate. Indeed, records of the time suggest Phnom Penh was more Vietnamese than Khmer. These days the majority of Cambodia’s commercial fishing is accounted for by impoverished ethnic Vietnamese fishing families; predominantly Buddhist, they live in floating villages on the Tonle Sap and Mekong River, moving around with the annual inundation. Government estimates put the number of ethnic Vietnamese living in Cambodia at around 100,000, but given the difficulty of monitoring the large number who live in floating villages, the true figure is thought to be much higher.
Historically, Cambodians have long entertained feelings of hostility towards the Vietnamese, who are all too often referred to using the derogatory Khmer term, Yuan. The roots of this resentment go back to the Vietnamese annexation of the Mekong delta in the seventeenth century. Tensions were exacerbated during the brief period of Vietnamese rule over the whole country, during which time they tried to impose their language, names and mores on the Khmer. The situation was aggravated during the French protectorate, when Vietnamese clerks were installed in Cambodia’s administration, and not helped when the French redrew the Cambodia–Vietnam border in favour of the Vietnamese after World War II.
You’re unlikely to witness any overt racism today, despite the recent surge in anti-Vietnamese feeling stirred up by Sam Rainsy’s Cambodian National Rescue Party (see The 2013 elections and after), who accuse the Vietnamese of taking Cambodian jobs and lands. Even so, it’s as well to note that no Cambodian would be seen dead in the pointed hats worn by Vietnamese rice farmers, and that the country’s current leader, Hun Sen, is often accused by his opponents of being a “Vietnamese puppet”.