As long as your list is legitimate, and everyone who is on it has explicitly opted in to receive emails from you, there is no limit to the mailing list size that you import.
What if I have a large list?
If you try to import a really big list, you will be asked to undergo a quick verification review with the Substack team.
Tip: For faster uploading times for importing extra large lists, try dividing them into multiple .csv files and importing them onto your account.
