Telstra will slash pay-as-you-go fees for international mobile data roaming from $15.36 to $3 a megabyte.
The telco said in a blog post it would also significantly expand the data limits for its 'casual traveller data packs'.
Customers are also to be sent usage alerts every time they run through 20 MB of mobile data while roaming, the telco said.
The incumbent is the last of Australia's big three mobile telcos to move on astronomical mobile roaming fees.
Earlier this month, Optus introduced new zoning arrangements and fees for international roaming, that see data usage charged at between 50 cents and $1 a megabyte, far cheaper than Telstra's cut price offer.
Optus also plans to introduce a $10-a-day travel pack in November that includes unlimited talk and text and 30 MB of data.
It currently offers prepaid travel packs for mobile data at $45 and $90-a-month tiers.
Vodafone has also been making changes to its international roaming plans, though its pay-as-you-go rates remain high at 1 cent a kilobyte ($10.24 per megabyte) for customers on a plan, or five times that for prepaid customers.
For $5 a day, Vodafone now allows customers to roam with the same features and allowances of their domestic plan, but the available countries are limited.