No and no on roaming and calling Korea. Korea is not on the list Global Pass works in so no roaming their. Korea is not on the list of countries you can call or text to. To see countries click the following link https://www.visible.com/plans/# and scroll down under the plus plan click on either the calling 30+ countries or texting 200+ countries, it is not on either.
As for receiving a call from Korea that might be possible if the person calling you can call US numbers, they may incur charges though but you shouldn't.
