Is this CoreESIM New Zealand plan also valid for travel to Australia?

This specific CoreESIM plan is exclusively for use within New Zealand and does not extend coverage to Australia. While many travelers combine these two destinations, they operate on separate mobile network infrastructures. If your itinerary includes both New Zealand and Australia, you would need to purchase a separate CoreESIM plan tailored for Australia, or consider a regional Oceania eSIM package that explicitly covers both countries.