Is it possible to check my ETA’s validity?

Yes, it is.
 
Clients can definitely check their ETA status via the Australian government’s website. For ETA validity, you can go here. Basically, an ETA is valid 12 month period from the date the ETA is granted or until the expiry date of your passport, whichever is earlier.

Originally published at https://blog.traveleta.com.au/how-do-i-check-the-status-of-my-eta on January 27, 2017