Travel in asia

Hi, I'm travelling for 3 weeks in Asia and will be visiting Vietnam, Cambodia and Thailand and spending a week in each country.
It's not clear from the website whether the add on I buy for Vietnam will also cover Cambodia etc.
Can anyone help with this as the alternative is buying an esim from Airalo as this covers all three countries.

Thank you.

Lebara doesn't offer regional roaming packages at moment just countries.
A lot of travellers use EsimDB