What port is used for IMAP over SSL (IMAPS)?

IMAP over SSL (IMAPS) uses TCP port 993. It is the encrypted counterpart to ordinary IMAP, which traditionally listens on port 143. The secure connection protects credentials and message traffic as the email client communicates with the server.

IMAP stands for Internet Message Access Protocol. Unlike POP3, IMAP is designed to keep messages on the server and synchronize folders, read status, and deletions across multiple devices. That makes it useful when someone checks the same mailbox from a phone, laptop, and web browser.

Port 993 is associated with implicit TLS: the client starts an encrypted session immediately. A different setup uses port 143 with STARTTLS, where the connection begins in plain text and is upgraded to encryption. This distinction explains why 143 sometimes appears in configuration guides. The other options are commonly confused email ports: 587 is normally used for authenticated message submission, 465 is also associated with secure submission, and 995 is POP3 over SSL.