No flag is reported although all surface vessels wear a "racing stripe," as seen here, which should in turn be its flag, following other Coast Guards from around the world who replicate the same pattern painted/applied to vessels, as their flag (i.e. Colombian Coast Guard). Esteban Rivera, 13 February 2016
Viet Nam Coast Guard (Vietnamese: Cảnh Sát Biên Việt Nam, CSB) (Coast Guard Viet Nam) is a Branch within the Viet Nam People's Army. It was established by President Tran Due Luong's order No. 3-L/CTN (7 April 1998), announcing the Ordinance on the Vietnam Coast Guard, which would be approved by the Tenth National Assembly of Vietnam on 28 August 1998.
Source: Wikipedia article Esteban Rivera, 13 Februry 2016
Doing some digging, I have found a pennant that is associated with the Coast Guard, but not exactly sure what main purpose it serves. It is a blue pennant, charged with the coat of arms of Vietnam. Behind the arms, there is an arrow. A picture of the pennant can be seen here. Zachary Harden, 14 February 2016
