Originally Posted by
Maji
I am not saying it is not doable, but it makes me nervous. The typical travel time from KIX to ITM on the limo bus is about 90 minutes. So, out of 3hrs 45min, the OP now has 2hrs 15min left. I believe KIX does not have the pressure of NRT, and the customs/immigration is faster. However, one has to account for a minimum of 30 minutes for that effect. Also, he should be in the ITM check-in bout 30 minutes before flight time. So, that leaves 1 hour 15 mins buffer. Any delays will make this connection hairy. My suggestion is ksandness's recommendation... to take the train, if possible.
Good luck.
The important question is whether your objective is to experience Japanese domestic air travel or to get to Tokyo with as little hassle as possible. Taking the train meets that criterion, especially with trains leaving every few minutes and no worries about getting stuck in traffic.