Airtel  Ussd Codes Send 3G to 121 to activate 3g on mobile you will get sms regarding if you don’t get option toactivate 3Git means you already on 3G just select plan now.You can also activate 3g from Airtel website. Also read GPRS Internet APN Settings fro all networks like Idea, Tata Docomo, Vodafone, BSNL, Videocon, Aircel, Reliance, MTNL, Loop