If your audience includes @comcast.net or @xfinity.com subscribers, there is an important change on the horizon that could affect your email deliverability and engagement.
What’s Changing?
Comcast is transitioning its email service to be fully powered by Yahoo Mail. This means that all @comcast.net and @xfinity.com email addresses will be handled by Yahoo infrastructure going forward.
The change requires Comcast users to migrate their email accounts to Yahoo by accepting new terms. If they do not, their email accounts — including inbox contents — will be deleted permanently by Comcast.
Migration Timeline
Mid-end 2025: Comcast began notifying users of the change.
By the end of 2026: Most users are expected to complete the transition.
Post-deadline: Unmigrated accounts will be deactivated and may begin bouncing.
We recommend proactively preparing now, especially if Comcast addresses make up a significant part of your subscriber base.
What Does This Mean for You?
1. Yahoo’s Filtering Rules Now Apply
Once Comcast emails are managed by Yahoo, they will be subject to Yahoo Mail stricter engagement-based filtering.
You may see a shift in inbox placement, especially if you previously had strong open rates from Comcast users.
2. Deliverability May Be Affected
Emails sent to inactive or unmigrated Comcast addresses will begin to hard bounce.
Over time, these addresses could be recycled into spam traps, especially if they remain on your list without engagement.
3. Engagement Will Be Evaluated Differently
Yahoo prioritizes:
Clicks, opens, and positive user actions
Penalizes deletes-without-reading, spam reports, and low engagement
This means your reputation with Yahoo will directly impact delivery to Comcast users.
Action Required: Set Up Yahoo Postmaster Tools
To protect and monitor your sender reputation, we recommend setting up Yahoo Postmaster. Emercury will provide any required DNS records you need to add to set up Yahoo Postmaster.
Best Practices to Prepare
Segment your list: Create a segment for Comcast addresses and monitor engagement.
Re-engage now: Send a targeted campaign encouraging opens/clicks before filtering shifts.
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