The best tools to import MBOX to ProtonMail are:
Advik MBOX Converter – Directly transfer MBOX to ProtonMail account quickly and accurately.
ProtonMail Import-Export App – imports MBOX directly (for paid plans).
ProtonMail Bridge – allows you to sync ProtonMail with email clients.
Mozilla Thunderbird – handles EML import and folder management.
Combining Advik MBOX Converter and Thunderbird + Bridge is a reliable way to import MBOX data even if you’re using a free ProtonMail account.
Advik MBOX Converter – Directly transfer MBOX to ProtonMail account quickly and accurately.
ProtonMail Import-Export App – imports MBOX directly (for paid plans).
ProtonMail Bridge – allows you to sync ProtonMail with email clients.
Mozilla Thunderbird – handles EML import and folder management.
Combining Advik MBOX Converter and Thunderbird + Bridge is a reliable way to import MBOX data even if you’re using a free ProtonMail account.