On November 11-15 in Jeju Island, South Korea will take place the Fourth World Mahjong Championship under the auspices of the World Mahjong Organization. Qualifying tournaments are being planned for China, though the specifics have not yet been announced. Member national organizations will also be able to register competitors directly.
Then December 4-6
in Hong Kong somewhere, World Mahjong Limited will hold the World Series of Mahjong with a prize package for the top 32 players of US$575,000. This one also plans qualifying events in multiple countries, as well as an online qualifying series.
CORRECTION: World Mahjong Limited informs me that they have not yet set a venue for the World Series of Mahjong.