Where can I buy an ISBN?

While an ISBN is not required to publish your journal on KDP, you may wish to have one if you want your book to be available in other retailers. I recommend buying ISBNs in bulk from Bowker.

All ISBNs are international but are assigned locally.

"Bowker is the official ISBN Agency for publishers physically located in the United States and its territories (Puerto Rico, Guam, US Virgin Islands, Northern Mariana Islands, American Samoa, as well as military bases and embassies. If an ISBN is obtained from a source other than the official ISBN Agency, it might not identify the publisher of the title accurately. This can have implications for doing business in the publishing industry supply chain."

You can find more info on their website here.

To find your local ISBN Agency outside of the US, go to this site here -->