Starting today, you’ll be able to catch Raikou, Entei or Suicune depending on what region you’re in. As with the last legendaries, you’ll need undertake Raid Battles in order to get them.
The below Pokemon that you can currently catch in your region are below:
Raikou – the Americas
Entei – Europe and Africa
Suicune – the Asia-Pacific region
Don’t stress out if you’re not going to be visiting each region in the world over the next few weeks. Starting September 30th, all three Pokemon will move to a new location until October 31st where they’ll make their final stop.