Investigators found more than 4,000kg of illegal ivory on public display in nine cities in the three countries targeted.
They say that represents the tusks of more than 760 elephants - even though recent statistics showed there were no more than 543 of the creatures left.
Buyers
However, the report shows that it is not only the countries who are responsible for the trade.
The main buyers of ivory are tourists and other overseas visitors from France, Italy, China, South Korea and the US.
Hear story 
Play our Poacher Patrol game
Click here to talk animals
Try the elephant quiz
