Set up a password-protected email in Proton Mail Free

Proton Mail Free can password-protect a message sent to someone using another email service. The recipient can open it in their browser without a Proton account, using a password you share separately.

The screenshot shows a fictional draft. Sending, recipient access and replies follow Proton's documentation (opens in a new tab); we have not tested delivery or the recipient's steps.

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1. Prepare the message

1. Click New message. Enter the intended non-Proton recipient, subject and message.
2. For practice, use fictional text and reader@example.com. That is an example address; do not send to it.
3. Click the lock control at the bottom, labelled External encryption.

2. Set a separate message password

1. Enter a new message password. Do not use your Proton account password.
2. Leave the optional hint empty if it would reveal the answer.
3. Click Set encryption. Check the blue lock beside the recipient and expiry notice.

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Proton Mail Encrypt message form with a masked example password and Set encryption button

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3. Check expiry before sending

Use Edit beside the expiry notice if you need a shorter period. The maximum is 28 days. If you close and reopen a draft, check the encryption and expiry again. Check the real recipient address and intended content before clicking Send.

Proton says the recipient chooses Unlock message in the notification, enters the password and clicks Read message. Tell them to verify the Proton destination before entering it.

To reply, the recipient selects Reply securely in the open browser message, writes a response and clicks Send. Proton limits recipients without a Proton account to five replies per password-protected email (opens in a new tab).

If you set a shorter expiry, Proton says the email and attachments are deleted from Sent when it expires (opens in a new tab). Keep any record you need securely before sending.

If the recipient cannot open it

Check the password through your separate channel and whether the message expired. Expiry controls access to the hosted message; it cannot retract text someone already copied or saved.

To practise the encryption controls without sending, start with Proton Mail Free (opens in a new tab) and use fictional text. Check the recipient, separate message password and expiry before sending any real message.

Source: Password protection, expiry and replies (opens in a new tab).