WiFi w/out SIM?

I'm heading to SE Asia for a month and was originally planning on using my iPhone4 with a local SIM card, but it appears the unlock will have to wait as I am currently running 4.21. I always remove the AT&T card when I travel to avoid any billing surprises upon my return home. Will I be able to access a network over there using WiFi without the card? I have other phones that I will use for calls, but would like the ability to access the internet... es possible?

TIA,
Steve

 

Thanks for the confirmation, Nino3G.