Yes you can use your optus mobile in Patong...
I have brought my phone with me on all my trips, and have not had a problem and i am with optus as well. One thing though, is that you must make sure that you do have international roaming activated....once enabled, you will find that your phone will auto selcet the strongest carrier and will recieve numerous msg's from the telco's welcoming you to Thailand and offering their services
. I Agree with livinLOS, watch out for incoming calls, as you will have to pay for these as well as calls made from your mobile. When i fist went to patong i recieved a couple calls from mates back in australia though all was fine until i got back and recieved my bill from optus..... not a nice suprise
