Japanese wagyu is currently exported to Cambodia, Hong Kong, Taiwan, the United States, Singapore, EU, and other countries.
It is traded for 6,838 JPY per kg (approx. 65 USD) in 2019.
A large amount is imported by Cambodia; it is considered that the imported beef is re-exported to China, which banned beef from Japan due to bovine spongiform encephalopathy (BSE). (As of January 2021, China is planning to restart imports of wagyu shortly.) In the countries or regions that can import wagyu, you should be able to get it through traders specializing in Japanese ingredients.
In places where Japanese wagyu is hard to come by, because of the issues such as the restriction on imports, shipping costs and tariffs, many Japanese restaurants use Overseas Wagyu instead.