If you’re in Singapore, it’s available on VIU.
If you’re not, then you might need to wait a week, since it will be available on KBS World’s youtube channel starting next Monday. They’re good about hosting a lot of shows that are subbed, but they only post them a week after airdate.
I don’t believe it’s available on Dramafever or Viki (at least, not yet).
(Or you can download it/watch it on whatever the latest dramacool type sites are, but I presume you’re talking about legal streaming sites.)
The Obsessive Dilettante 