Buyers look past Outlook when they are not on Microsoft 365 and do not want a suite for a mail window, when the split between classic and new Outlook adds support work, or when they want a lighter or more team-minded inbox. Most go to eM Client or Thunderbird for a plain desktop client, Spark or Missive for shared work.
Visibility in our rankings can be paid for. Payment moves a vendor's position within
the shortlist; it never adds a vendor, and it never changes a word of the review or of this page. The first three alternatives
go to challengers, vendors outside the best-known brands in a category, wherever the category has them; the
established names follow in their ranked order. How it works:
placement disclosure · editorial process.
What each alternative does differently
1. eM Client
Desktop mail, calendar, contacts and tasks, bought once · Czech Republic
Closest in feel: a desktop client with mail, calendar, contacts and tasks, and a one-time license as an option beside the yearly one. It has no shared-inbox layer, so team routines stay outside it. Home use is free on two accounts, so a company needs a paid license.
Switch from Microsoft Outlook if you want a Windows or Mac desktop client with a one-time license option.
Pricing: Free for home use with 2 accounts; Personal 49.95 euros per year or 74.95 euros once; Business 59.95 euros per year or 89.95 euros once. (free plan)
Full review: #7 of 12 in our ranking ·
Visit eM Client →
2. Thunderbird
Free open source desktop mail, calendar and contacts · United States
Free, open source desktop software with mail, calendar and contacts on Windows, macOS and Linux, plus an Android app. It reads any IMAP mailbox, including Exchange Online while IMAP stays enabled. Nobody sells support or admin policies for it, so IT manages it by hand.
Switch from Microsoft Outlook if you want a free client with no vendor tie and can live without central admin.
Pricing: Free and open source, funded by donations; no paid plan was listed on the pages we fetched. (open source)
Full review: #3 of 12 in our ranking ·
Visit Thunderbird →
3. Spark Mail
Unified inbox app with a free tier and team plans · Ireland
A unified inbox for many accounts with smart sorting, snooze, send later and shared drafts, plus a free plan. It is built for teams that comment on mail together, not for enterprise calendars. Rooms, delegation and compliance holds remain with your mail host, not this app.
Switch from Microsoft Outlook if you juggle several accounts and want a lighter inbox with team features.
Pricing: Free plan with unlimited accounts; Plus at 8.25 euros per user per month billed yearly (10 euros monthly); Pro at 19.08 euros yearly (22 euros monthly); Enterprise by quote. (free plan)
Full review: #1 of 12 in our ranking ·
Visit Spark Mail →
4. Missive
Collaborative inbox for teams that run on email · Canada
A shared inbox first: internal comments, assigned conversations, tasks from email, rules and SMS or social channels sit in one place. It suits support and sales teams, not solo users. It sits on top of your existing mail accounts, so it does not replace the mail server.
Switch from Microsoft Outlook if your team shares mailboxes and spends its day assigning and discussing messages.
Pricing: Starter $14, Productive $24 and Business $36 per user per month billed yearly, with a 30-day free trial that needs no credit card. (free trial)
Full review: #2 of 12 in our ranking ·
Visit Missive →
5. Gmail
Google's web inbox with custom domains and Gemini · United States
Moving here means moving the mailbox, not just the app: Gmail is sold through Google Workspace with custom domains, IMAP access and an admin console. Calendar and files come as part of that suite. It replaces the Microsoft 365 mail service as well as the client.
Switch from Microsoft Outlook if you are ready to move the whole mail and calendar service to Google Workspace.
Pricing: Sold through Google Workspace: Starter 6.80 euros, Standard 13.60 euros and Plus 21.10 euros per user per month on annual commitment; a 14-day free trial; Enterprise by quote. (free trial)
Full review: #4 of 12 in our ranking ·
Visit Gmail →
6. Shortwave
AI-first email app for Gmail and Outlook teams · United States
An AI-first client that works with Gmail and Outlook accounts, with AI search, filters, split inbox and bundles. It adds a layer to your mailbox instead of replacing Exchange. Price rises with AI quotas, and your messages pass through its models, which a security review should cover.
Switch from Microsoft Outlook if you keep your mailbox but want an AI layer for triage and search.
Pricing: Business $30, Premier $45 and Max $120 per seat per month, with a 14-day free trial; AI usage quotas rise with each plan. (free trial)
Full review: #6 of 12 in our ranking ·
Visit Shortwave →
7. Superhuman
Fast AI-native inbox for Gmail and Outlook · United States
A speed-focused client for Gmail and Outlook accounts with split inbox, auto drafts, follow-up reminders and an AI assistant. It pitches individuals and sales or executive roles. We could not read a list price, so request a quote before you plan a rollout.
Switch from Microsoft Outlook if you want a fast keyboard-driven inbox for executives and sellers on top of Outlook mail.
Pricing: Per-user subscription; the pricing page we fetched showed only a title, so we cannot state a price or a free plan. (none)
Full review: #12 of 12 in our ranking ·
Visit Superhuman →
8. Mailbird
Windows and Mac unified inbox with app integrations · United States
A Windows and Mac unified inbox with app integrations, snippets, snooze and send later. It has a free plan for one account and a one-time license option. Collaboration is thin, and add-ons are priced separately, so check what the licence covers before you count seats.
Switch from Microsoft Outlook if you want a plain multi-account Windows client and prefer to pay once.
Pricing: Free for 1 account; Premium 4.03 euros per user per month billed yearly; or pay once 99.75 euros per user, with extra add-ons priced separately. (free plan)
Full review: #8 of 12 in our ranking ·
Visit Mailbird →
9. Mimestream
Native macOS email client built on the Gmail API · United States
A native Mac app built on the Gmail API, with Gmail labels, server-side filters and snooze. It works with Google accounts only, so it does not open an Exchange mailbox at all. It is a replacement for Outlook for Mac users who also use Gmail, not for Exchange shops.
Switch from Microsoft Outlook if you use a Mac, your mailbox is on Google and you want a native app.
Pricing: Individual $49.99 per year or $4.99 per month; Group plans for teams add central billing and seat management; 14-day free trial with no credit card. (free trial)
Full review: #10 of 12 in our ranking ·
Visit Mimestream →
10. HEY
Email and calendar service with a built-in screener · United States
Email as a service from 37signals with a screener for new senders, built-in calendar and a custom-domain option. It does not support IMAP or POP, so it cannot read your other accounts. You move to a HEY address or domain, which suits individuals more than Exchange teams.
Switch from Microsoft Outlook if you are willing to change address and want a different way of handling new senders.
Pricing: HEY for You $99 per year; HEY for Domains $12 per user per month ($10 for the first user); 30-day free trial with no credit card. (free trial)
Full review: #9 of 12 in our ranking ·
Visit HEY →
11. Fyxer AI
AI assistant that organizes, drafts and takes notes · United Kingdom
Not an inbox replacement: an assistant that sorts mail, drafts replies, takes meeting notes and helps with scheduling on top of Gmail or Outlook. You keep your mail service and client. Credits are metered, and it is aimed at client-facing professionals rather than shared-mailbox teams.
Switch from Microsoft Outlook if you keep Outlook mail but want an assistant to sort and draft for you.
Pricing: Pro $37 per person per month on annual billing ($49 monthly); Team $64 per person annual ($99 monthly); Enterprise by quote; 14-day free trial. (free trial)
Full review: #11 of 12 in our ranking ·
Visit Fyxer AI →
Questions and answers
Can I export my mail from Outlook?
Yes, to an Outlook Data File (.pst) from classic Outlook, one account at a time. New Outlook can export a .pst as well under Settings, Files, Export, but Microsoft says calendar and contacts in a .pst are not available there and importing a .pst is not supported. Other clients may not read .pst, so test first.
Can I move contacts out of Outlook?
Yes, as a .csv file through the Import/Export wizard in classic Outlook. Microsoft says to open the file in Excel only to check it and to close it without saving, otherwise it may no longer import. A UTF-8 encoded file works for all languages.
Will other email apps connect to my Exchange Online mailbox?
Only if POP3 or IMAP4 is enabled for it. Microsoft says those protocols are disabled by security defaults and blocked when Basic authentication is switched off. Thunderbird is named by Microsoft as one program that can connect over them, but IMAP gives basic mail, not the full calendar features.
Do I have to leave Microsoft 365 to change email client?
No. Exchange Online is a service, Outlook is one client for it. Microsoft documents Outlook on the web, POP and IMAP access as other routes, so you can change app and keep the mailbox and its shared mailboxes. Leaving the mailbox is a separate decision.
What happens to my data if I cancel Microsoft 365?
It is kept for a while and then deleted. Microsoft's lifecycle table shows 30 days expired and 90 days disabled for most offers, with data open to admins only in the disabled stage. After deletion, a new subscription does not restore it, so back up first.
Can I cancel a Microsoft 365 business subscription at any time?
Not always with a refund. For a Microsoft Customer Agreement account, a prorated credit or refund applies only within seven days of the start or renewal. After that you turn off recurring billing and keep access until the term ends. Check your agreement type.
Can I stop Windows from installing the new Outlook?
Not on all builds. Microsoft says Windows 11 builds after 23H2 have it preinstalled with no way to block it, though admins can remove the app package. On Windows 10 a registry value blocks the install. Alternatives you deploy need to coexist with it.
