Your au phone might actually work:emiko08 wrote: i have a au(kddi) cellphone, and a 3g vodafone.
would be hoping my kddi phone could be used in korea though cause
my 3g cellphone is a normal simcard and not a usim card.
http://www.au.kddi.com/kaigai/gp/world_area/korea.html
But best to heed Plavt's advice and check with them directly if your subscription plan/phone model allows this.