A free email client comes installed and ready for use with macOS, and macOS Mail is not a bad program at all. However, you might want to examine its free alternatives. Here are the best free email clients available for macOS. Give them a try.
Available for Windows, Mac, Linux. Back in 2016, Nylas Mail hit the scene and looked as if it’d be the desktop email client to put all other desktop email clients to shame. I wouldn't vote for it as the best free email client for the same reason as the reviewer says: 'eM Client is certainly one of the better looking clients available for Windows however, the free version is held back by the account restriction to only two email addresses.'
MacOS Mail
What We Like
Included in the Mac operating system.
Supports smart folders and robust filters.
Markup tools for annotating photos or PDFs email attachments.
VIP user notifications.
What We Don't Like
Basic design that lacks customization features.
No option to snooze emails.
Hasn't had a major design upgrade in years.
The Mail application that ships with macOS and OS X is solid, feature-rich and spam-eliminating software that is also an easy-to-use email client. Optimized to work on the Mac, the Mail app is trouble free and full featured. It can handle all your email accounts in one place.
Spark
What We Like
Clean, modern design.
Quick Replies feature for sending short, templated responses.
Smart mailboxes.
Supports multiple email accounts.
What We Don't Like
Slow tech support.
Questionable privacy policy.
Doesn't support many services.
Spark is an impressive email program that auto-organizes your inboxes and lets you postpone email easily as well as send quick one-click replies. Spark's 'Smart Inbox' bubbles messages that are important to you to the top, and uses categories of Personal, Notifications, and Newsletters.
Spark's scheduling feature allows you to assign a time period during which it will send a particular message. Select from times later today, in the evening, tomorrow, or on any date.
Mailspring
What We Like
Integrates with Gmail, iCloud, Office 365, Outlook, and Yahoo
Supports snoozing.
CPU and battery efficient.
What We Don't Like
Some features limited to paid subscription.
Doesn't support Exchange accounts.
Mandatory Mailspring ID.
Aimed at the professional email user, Mailspring boasts mail merge, reminders, and the option to schedule mail—all available in a pro edition.
With the free version, you get a clean, highly productive and expandable email program that includes thrills such as link and open tracking, quick reply templates, and undo send. However, the free edition is limited to 10 accounts.
Mozilla Thunderbird
What We Like
Flexible filtering system.
Many available plug-ins.
Tabs for navigation.
Easy to configure.
What We Don't Like
Best Email Client For Windows 10
Rudimentary design.
Not as user friendly as other clients.
No longer in development.
Mozilla Thunderbird is a full-featured, secure, and functional email client. It lets you handle mail efficiently and filters away junk mail. Thunderbird is no longer in active development except for security updates, but it supplies a streamlined interface and a powerful email package.
Mozilla SeaMonkey
What We Like
All-in-one internet suite that includes email.
Customizable toolbars.
Best Email Client For Android
What We Don't Like
Free Email Client For Mac
Outdated interface.
Some features not intuitive.
No mobile device support.
Never underestimate Mozilla. The company built SeaMonkey, the email component of its open source browser, on the same Mozilla platform as Firefox 51. It delivers HTML5, hardware acceleration, and improved JavaScript speed. It is a solid performer, full featured and usable.