Comparison · Updated October 2026 · We design, deploy and support all three
Mimecast vs Proofpoint vs Defender for Office 365:which is right for your business?
A side-by-side look at deployment, protection, archiving, continuity, training and cost for Microsoft 365 companies in Oman, the UAE, Qatar and Saudi Arabia.
Compare for your team
Three quick questions, then your details.
The short answer
Mimecast vs Proofpoint vs Microsoft Defender for Office 365 comes down to what you need beyond filtering.
Defender for Office 365 Plan 1 is already in Microsoft 365 Business Premium and E3. 
Mimecast adds an independent archive and continuity across platforms. 
Proofpoint adds deep threat protection, or a Microsoft 365 bundle for smaller firms. Gulf Infotech supports all three.
What we compared
- Microsoft Defender for Office 365
Microsoft Defender for Office 365
Compared on this page
Mimecast
Compared on this page
Proofpoint
Compared on this page
Disclosure
Gulf Infotech is a Microsoft Solutions Partner for Modern Work and also deploys and supports Mimecast and Proofpoint, so this comparison has no reason to favour one. We also deploy Zoho eProtect, Zoho's secure email gateway with archiving, for Zoho users and for teams that want filtering and an archive in one product.
Verdict
The short verdict
Start with Microsoft Defender for Office 365
If you are on Microsoft 365 Business Premium or E3. Plan 1 adds Safe Links, Safe Attachments and impersonation protection, at no extra cost on those plans. Many firms under 300 users need nothing more, once DMARC is in place.
Learn more: Bitdefender vs Microsoft Defender for BusinessChoose Mimecast
If you need a separate email archive, mail continuity during outages, or one policy across Microsoft 365, Google Workspace and on-premise email.
Learn more: Mimecast email archivingChoose Proofpoint
If invoice fraud and impersonation are your top risk and you have a security team (Core Email Protection), or you want one Microsoft 365 bundle with backup, archiving and DMARC tools (365 Total Protection).
Side by side
Mimecast vs Proofpoint vs Defender for Office 365: how do they compare?
| Feature | Microsoft Defender for Office 365 | Mimecast | Proofpoint |
|---|---|---|---|
| How it connects | Microsoft Defender for Office 365Built into Microsoft 365 | MimecastMX gateway (in line) or API | ProofpointCore: API or inline gateway; 365 Total Protection: MX or API |
| Mail platforms | Microsoft Defender for Office 365Microsoft 365 | MimecastMicrosoft 365, Google Workspace, on-premise | Proofpoint365 Total Protection: Microsoft 365. Core: confirm per platform |
| Links and attachments | Microsoft Defender for Office 365Safe Links, Safe Attachments (Plan 1) | MimecastOn-click link protection, attachment sandboxing | ProofpointSandboxing, URL rewriting |
| Impersonation and BEC | Microsoft Defender for Office 365User and domain impersonation protection (Plan 1) | MimecastComputer-vision detection of brand and login-page impersonation, QR-code phishing | ProofpointBEC detection; Email Fraud Defense for lookalike domains |
| Teams, SharePoint, OneDrive files | Microsoft Defender for Office 365Safe Attachments and Safe Links cover them (Plan 1) | MimecastCollaboration tools mentioned; confirm Teams scope with us | ProofpointNot stated for email products |
| Separate archive | Microsoft Defender for Office 365No | MimecastYes, Mimecast Email Archive | ProofpointYes, in 365 Total Protection |
| Continuity during outage | Microsoft Defender for Office 365No | MimecastYes, with MX deployment | ProofpointYes, in 365 Total Protection |
| Awareness training and phishing simulation | Microsoft Defender for Office 365Attack simulation training (Plan 2) | MimecastMimecast Engage | ProofpointZenGuide; phishing tests in 365 Total Protection |
| DMARC tools | Microsoft Defender for Office 365Not listed in Defender plans | MimecastDMARC Analyzer | ProofpointDMARC Manager (365 Total Protection), Email Fraud Defense |
| Investigation and response | Microsoft Defender for Office 365Real-time detections (Plan 1); Threat Explorer, automated investigation and response (Plan 2) | MimecastAutomated threat remediation | ProofpointRemoval of malicious mail after delivery |
Takeaway:Defender is the most integrated, Mimecast the most platform-neutral, and Proofpoint the broadest bundle for small Microsoft 365 firms or the deepest option for security teams.
In detail
How much does each one cost?
Defender for Office 365 comes inside some Microsoft 365 plans:
| Microsoft 365 plan | Defender for Office 365 | USD per user per monthOMR per user per monthAED per user per monthQAR per user per monthSAR per user per month |
|---|---|---|
| Business Premium with Copilot | Defender for Office 365Plan 1 | USD per user per monthOMR per user per monthAED per user per monthQAR per user per monthSAR per user per month32.0012.416117.76116.48120.00 |
| E3 | Defender for Office 365Plan 1 | USD per user per monthOMR per user per monthAED per user per monthQAR per user per monthSAR per user per month39.0015.132143.52141.96146.25 |
| E5 | Defender for Office 365Plan 2 | USD per user per monthOMR per user per monthAED per user per monthQAR per user per monthSAR per user per month60.0023.280220.80218.40225.00 |
Converted from the USD list prices at 1 USD = 0.388 OMR · 3.68 AED · 3.64 QAR · 3.75 SAR, for reference. VAT is extra where it applies.
Converted from the USD list prices at 1 USD = 0.388 OMR · 3.68 AED · 3.64 QAR · 3.75 SAR, for reference. VAT is extra where it applies.
Converted from the USD list prices at 1 USD = 0.388 OMR · 3.68 AED · 3.64 QAR · 3.75 SAR, for reference. VAT is extra where it applies.
Converted from the USD list prices at 1 USD = 0.388 OMR · 3.68 AED · 3.64 QAR · 3.75 SAR, for reference. VAT is extra where it applies.
Prices as of October 2026 · per user per month, billed annually (annual upfront commitment) · exclude VAT (Oman and UAE 5%, Saudi Arabia 15%, Bahrain 10%, Qatar and Kuwait none). Defender for Office 365 is also sold as an add-on to other Microsoft 365 plans, at Microsoft's list price of $2.00 per user per month for Plan 1 and $5.00 for Plan 2, supplied in every country. Mimecast and Proofpoint are licensed per user, typically per year, and quoted by modules for your requirement.
The real cost question is overlap. A company on Business Premium already pays for Plan 1. Adding Mimecast or Proofpoint makes sense when you need what Plan 1 does not give you: an archive, continuity, a second detection layer, or cover for non-Microsoft mailboxes.
Deployment, migration, training and support are charged separately.
Strengths
It is already licensed for many Microsoft 365 companies, needs no MX change, and protects Teams messages and files in SharePoint, OneDrive and Teams as well as email. Alerts sit in the same Microsoft Defender portal as device alerts from Defender for Business. Plan 2 adds Threat Explorer, automated investigation and attack simulation training for companies with someone to use them.
Microsoft Defender for Office 365- How it connectsBuilt into Microsoft 365
- Mail platformsMicrosoft 365
- Links and attachmentsSafe Links, Safe Attachments (Plan 1)
Mimecast is a separate system in front of your mail. That gives you continuity when Microsoft 365 or Exchange is down, an independent, tamper-resistant archive with legal hold, and one policy for companies running Google Workspace, Microsoft 365 and on-premise mail together. It also suits firms that want awareness training and DMARC reporting from the same vendor. See Mimecast email security.
Mimecast- How it connectsMX gateway (in line) or API
- Mail platformsMicrosoft 365, Google Workspace, on-premise
- Links and attachmentsOn-click link protection, attachment sandboxing
For larger organisations with a security team, Core Email Protection, with add-ons such as Email Fraud Defense, Adaptive Email DLP and Account Takeover Protection, targets invoice fraud and impersonation in depth. For small and mid-sized Microsoft 365 firms, 365 Total Protection puts filtering, encryption, archiving, continuity, Microsoft 365 backup, DLP, DMARC management and training in one subscription. See Proofpoint email security.
Proofpoint- How it connectsCore: API or inline gateway; 365 Total Protection: MX or API
- Mail platforms365 Total Protection: Microsoft 365. Core: confirm per platform
- Links and attachmentsSandboxing, URL rewriting
Step by step
How hard is it to switch?
The archive is the slowest part. Plan it before renewal.
- 01
Inventory
domains, connectors, allow and block lists, and any archive you need to keep.
- 02
Authentication
update SPF, DKIM and DMARC for the new sending path. See DMARC setup.
- 03
Parallel run
for API products, typically a short period in monitor mode; for gateways, an MX change at a quiet time.
- 04
Archive
if leaving Mimecast or Proofpoint archiving, export or keep the old archive licensed until your retention period allows.
- 05
Tuning
quarantine and false positives reviewed with your team in the first weeks.
Frequently asked questions
Is Mimecast better than Proofpoint?
Neither is better for everyone. Mimecast is the usual choice when you need a separate archive, continuity and support for Google Workspace or mixed platforms. Proofpoint suits Microsoft 365 firms that want one bundle with backup and DMARC tools, and larger security teams that want depth against impersonation and account takeover. We deploy both and compare them on your mail flow.
Is Defender for Office 365 enough on its own?
For many companies under 300 users on Business Premium or E3, yes, once SPF, DKIM and DMARC are set up. Plan 1 adds Safe Links, Safe Attachments and impersonation protection to Microsoft's built-in filtering. Add Mimecast or Proofpoint when you need an independent archive, continuity during outages, a second detection layer or cover for non-Microsoft mail.
What is the difference between Defender for Office 365 Plan 1 and Plan 2?
Plan 1 adds prevention: impersonation protection, Safe Attachments and Safe Links across email, Office apps and Teams, plus real-time detections. Plan 2 adds investigation and response: Threat Explorer, Threat Trackers, automated investigation and response, advanced hunting and attack simulation training. Plan 1 is in Business Premium and E3; Plan 2 is in E5. Both are also sold as add-ons, at $2.00 (Plan 1) and $5.00 (Plan 2) per user per month on Microsoft's list.
Can we run Mimecast or Proofpoint alongside Defender for Office 365?
Yes, and it is a common setup because Defender Plan 1 already comes with Business Premium. The two layers must be configured to work together, so connectors, allow lists and policies do not conflict and legitimate mail is not held twice. We set up both sides and test mail flow before switching over.
Which works with Google Workspace?
Mimecast supports Google Workspace directly, with MX-based protection, archiving and continuity. Defender for Office 365 is for Microsoft 365 only. Proofpoint's 365 Total Protection is built for Microsoft 365; for Core Email Protection we confirm support for your setup with Proofpoint before quoting. Google Workspace also has its own built-in spam and phishing filtering.
Which is cheapest?
Defender for Office 365, if you already pay for Microsoft 365 Business Premium at $32.00 or E3 at $39.00 per user per month billed annually, because Plan 1 is included. Mimecast and Proofpoint are added costs, priced per user by modules and quoted. Prices exclude VAT and are as of October 2026. Compare on what you actually need, not on filtering alone.
Not sure which one fits?
Tell us your user count, mail platform, current Microsoft licences and whether you need archiving, and we will recommend one and send a quote.
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