Last name Wansen (万森 
, Wansen 
, หวันเส็น ) , globally, is quite a rare cognomen. The surname Wansen is habitual in Thailand, where it is a rare surname, Finland, where it is a very rare surname, and Philippines. Measured by absolute frequency, it is commonest in China, Thailand, and Philippines. More prevalently, Wansen is the forename as well as the last name.