Starting today, Amazon EC2 I3en instances are available in US West (N. California) and Asia Pacific (Seoul) AWS Regions. I3en global availability now includes the Asia Pacific (Tokyo, Seoul), Europe (Frankfurt, Ireland), US East (N. Virginia, Ohio), and US West (Oregon, N. California) AWS regions. 

from Recent Announcements https://aws.amazon.com/about-aws/whats-new/2019/07/amazon-ec2-i3en-instances-now-available-ncalifornia-asia-pacific-seoul/