Australian Embassy has not been established in Andorra yet.
You should applying online for Australian eVisitor/ETA online for saving time. By that way, you will get the Australian eVisitor/ETA approval letter before leaving Andorra for Australia.
Please visit our visa processing to know how to apply for Australian eVisitor/ETA step by step safer and faster.
If you have any further questions, please feel free to contact us. Thank you!