Customers with a Vodafone email address will have to switch at the end of November, when the telco plans to axe its email services after 20 years.
Email addresses affected include its Clear and Paradise services.
Vodafone had about 200,000 to 250,000 active email users but many operate dual email accounts, a Vodafone spokesperson said.
The accounts would be switched off on November 30, however, Vodafone has promised customers it will automatically forward emails from the closed accounts to a new email of the customer's choice, for as long as they are a Vodafone customer.
The telco was encouraging users to set up a free Microsoft or Google email account.