Google has extended its free SMS chat service to Indian users. The Gmail SMS feature is now accessible to Indian users along with 51 other countries in Asia, Africa and North America. Google had made this feature available to its users in some African countries in 2011. Using the free Gmail SMS service users can send text messages to mobile phones via Gmail Chat. Responses to the SMSs will appear as replies in Gmail Chat and conversations will be stored in users' Chat history, like regular chats.

This feature was activated for Indian users on October 10 and is available for regular Gmail users as well as those on Google Apps.

In India the free Gmail SMS service is available on eight major mobile service operators: Aircel, Idea, Loop Mobile, MTS, Reliance, Tata DoCoMo, Tata indicom and Vodafone (Delhi, Mumbai, Kolkata, Gujarat, Andhra Pradesh, Bihar, West Bengal & Andaman and Nicobar, Assam, North East).

This feature is not yet available on the Google Talk app, also referred to as GTalk, installed on computers. Users are initially given a credit of fifty messages and for every message sent the credit decreases by one and for each message received in response to a text message sent via Gmail Chat, the user's credit increases by five, up to a maximum of 50. When the SMS credit goes down to zero, one credit is added after 24 hours. Google has built in the credit limit to prevent misuse of its free SMS service for marketing/spamming.

Users can also 'buy' SMS credit, when they've run out of them, my sending a text message to their own phone and then by replying to that message. People who do not wish to receive SMSs sent from Gmail Chat can block future messages from the sender by replying to the message with the word 'BLOCK' and later if they wish to continue receiving messages they can reply to the message with 'UNBLOCK'.

If Gmail Chat SMS recipients in India do not wish to receive any messages on SMS from any Gmail user, they can stop the service from sending them messages by texting 'STOP' to +918082801060. To reactivate the service they can SMS 'START' to the same number. To send an SMS from Gmail, on the Gmail Chat interface type the phone number you want to send an SMS to and click Send SMS and then add the recipient's name and country, then click Save. Then write in the message in the chat window and press Enter. While sending SMS from Gmail Chat to phones is free, responding to Gmail SMSs from the phone may incur standard SMS charges.