Black and white Yoshis are the first to arrive down under.
Starting with today's Australian launch of Mario Tennis Open, the distribution of multicolored Yoshi characters has begun. As in other regions, Nintendo will slowly distribute additional Yoshi colours through QR codes over the next few weeks in an event they have dubbed "Yoshi Chase."
The first two variants to hit Australian shores are the black and white Yoshis, which can be found at EB Games and JB Hi-fi, respectively. The QR code will be posted somewhere in the stores for you to find and scan with your 3DS, and you must visit both stores if you want both colours.
Nintendo promises "many more" Yoshi variants will appear in the coming weeks. There is no news yet as to when these particular Yoshis will be available to Mario Tennis Open players outside Australia.