According to the announcement, “Trainers in 15 new countries and regions across Asia and Oceania can now officially download Pokémon GO from the Play Store or App Store. Discover Pokémon in the world around you! Countries and regions include: Brunei, Cambodia, Indonesia, Laos, Malaysia, Philippines, Singapore, Thailand, Vietnam, Taiwan, Papua New Guinea, Fiji, Solomon Islands, Federated States of Micronesia, and Palau.”
Gamers who are interested can fire up their respective app stores and download the app and start playing, although safe to say that there are probably players in those countries who have figured out a workaround before Niantic released the game for their countries. That being said, the release in these countries doesn’t really change the fact that many players are still upset at Niantic over the recent changes they’ve made, not to mention the various bugs that have made Pokemon unnecessarily difficult to catch.
In any case hopefully all of this can be addressed soon, but until then, enjoy!