Telecom chief executive Simon Moutter said Telecom knew data roaming charges were a pain-point for customers.
''Personally, it was a real bugbear of mine as a customer before I joined Telecom earlier this year. A flat fee provides certainty and puts an end to concerns about nasty bill shocks on your return home."
The new pricing plans start from Friday, December 21.
A feature is a flat daily rate for data roaming by postpaid customers across major travel markets.
Australia roaming would start at a reduced rate of $6 a day with a review in the middle of next year. Customers would pay $10 a day flat rate for data while travelling in the United Kingdom, United States, Canada, China, Hong Kong, Macau, Taiwan and Saudi Arabia. Telecom's fair use policy applied to those rates.
Data roaming charges would be slashed by 83% to 92% in other markets, although other charges would continue to be on a usage basis, Mr Moutter said.
The new postpaid pricing schedule also included new voice call roaming rates featuring a 35% cut in per-minute rate for Australia.
He acknowledged there was an element of financial risk for Telecom in the flat fee approach, but he believed it was a risk worth taking.
''We've been negotiating hard on new wholesale deals with overseas telcos that underpin our new pricing. At the same time, we've had to make assumptions on how customers' data use behaviour might change under the flat fee approach."
As an example, a customer who spent five days in the US and consumed 86.6MB of data would have saved $325.50 on the $10 per day flat rate, an 87% saving.
