Here is a list of top ten Asian countries according to the number of mobile phone users:

1. China - 644.8 million
2. India - 391.6 million

These two countries share 25 percent of total mobile phone users in the world, that is 1.04 billion subscribers of the world’s total number of 4.15 billion.

3. Indonesia - 144.6 million, followed by Japan.
5. Pakistan - 93 million
6. Vietnam - 73.2 million
7. Philippines - 71.7 million
8. Thailand - 62.7 million
9. Bangladesh 46.3 million
10. South Korea 46.2 million

The list seem to be symmetrical with the list of most populous countries and Bangladesh falling behind 3 places.

The top ten countries for mobile users in Asia have 3.48 billion people and 1.68 billion mobile users.

(source)