SMS warning to stop overseas phone bill pain for passengers Telstra has moved to cut down on bill shock for customers who use data while travelling overseas Source: Supplied TELSTRA has moved to cut down on bill shock for customers who use data while travelling overseas by today launching a new SMS warning system. Under the current system, Telstra customers receive a warning email when they connect to an international network. The new system keeps that warning email and sends a new SMS alert for every 20MB used overseas. The cost of using 20MB of data overseas depends on the customer's plan and on the country they are travelling to. But, for example, if a Telstra customer on a monthly plan travelled to the United States and used 20MB of data at $15.36 per MB, it would cost them about $307. Telstra Mobile director Tim Webber said the new SMS warning system followed recent changes to Telstra International Casual Traveller Data Packs, which range from $29 for 20MB to $1800 for 2GB. Mr Webber said customers should check with Telstra before travelling to make sure they are fully informed about potential costs and ways to avoid huge data costs on their trip.