Microsoft Defender for Office 365 Plan 1 vs Plan 2 (2026)

Microsoft’s Defender for Office 365 page lists Plan 1 at $2.00 and Plan 2 at $5.00 per user per month, paid yearly with annual auto-renewal (checked 18 October 2026). Microsoft Learn says Defender for Office 365 is available as an add-on to many Microsoft 365 subscriptions with cloud mailboxes. The same pricing page lists the Microsoft Defender Suite at $12.00 per user per month, requiring Microsoft 365 E3, or Office 365 E3 plus Enterprise Mobility + Security E3.

Microsoft’s licensing update “2026 M365 Packaging & Pricing Updates” (dated 16 February 2026) changed suite prices from 1 July 2026; existing customers keep their price until renewal. The table shows those USD list prices with Teams, per user per month. The Defender column follows Microsoft Learn and the June 2026 Defender blog.

Worked example at list price: a 250-user tenant on Microsoft 365 E3 that wants Plan 2 adds $5.00 × 250 × 12 = $15,000 per year. Moving the same tenant from E3 to E5 adds $21 × 250 × 12 = $63,000 per year, but buys much more than email security. Your agreement price may differ from list. Office 365 E5 ($38, now $41) is not covered by the plan examples Microsoft Learn gives; check the licensing service plan reference for your SKU.

Yes, from 2026. Microsoft’s Defender for Office 365 team announced on 17 June 2026 that Plan 1 is rolling out to Microsoft 365 E3/G3 and Office 365 E3/G3, with some protections turned on automatically. Microsoft’s licensing news page ("2026 M365 Packaging & Pricing Updates", dated 16 February 2026) says the features are complete by 1 August 2026; the Defender blog says "by Fall 2026". Microsoft Learn now lists Microsoft 365 E3/G3 as an example of a subscription that includes Plan 1.

What this means in practice: an E3 tenant that bought Plan 1 as an add-on can likely drop it at renewal. An E3 tenant comparing Plan 2 against a third-party tool should now compare against "E3 with Plan 1" as the baseline, not bare built-in protection. Check the Your products page in the Microsoft 365 admin center to confirm what your tenant has.

The same 2026 packaging update adds URL time-of-click protection to Office 365 E1 and Microsoft 365 Business Basic and Standard. That narrows, but does not close, the gap between those suites and Plan 1, which still adds Safe Attachments and impersonation protection.

Microsoft summarizes the ladder this way: built-in protection prevents broad, volume-based, known attacks; Plan 1 protects email and collaboration from zero-day malware, phishing and business email compromise; Plan 2 adds phishing simulations, post-breach investigation, hunting, response and automation. Microsoft does not document a separate mail-flow detection engine for Plan 2, so its value depends on whether someone will use Threat Explorer, AIR and hunting.

• You have a SOC or an MSSP working in the Defender portal: Plan 2 gives them Threat Explorer, Campaigns and AIR.
• You run Microsoft Defender XDR across endpoints and identities: Plan 2 brings email into the same incidents.
• You want Microsoft-native phishing simulation: attack simulation training is Plan 2 only.
• You are a lean IT team that reacts to user reports: Plan 1 gives you the prevention; Plan 2 features may go unused.
• You want to integrate a third-party ICES vendor into the Defender portal: Microsoft’s ICES Vendor Ecosystem requires Plan 2 or E5.

Even Plan 2 leaves some areas to other products or vendors. OAuth app governance is Defender for Cloud Apps, identity risk is Entra ID P2, and Google Workspace is out of scope. Microsoft also runs an ICES Vendor Ecosystem that lets three approved partners (Darktrace/EMAIL, KnowBe4 Defend Platform and VIPRE Integrated Email Security) pass verdicts into the Defender portal for Plan 2 and E5 customers.

Sentaro is an API-based email security platform for Microsoft 365 and Google Workspace, hosted in Sweden on Microsoft Azure. It runs alongside Plan 1 or Plan 2 rather than replacing them: Microsoft’s built-in protection and Defender stay in place for bulk and known attacks, and Sentaro adds its own engine, Vord, on top. For most EU teams without a dedicated SOC, that is a better use of budget than moving from Plan 1 to Plan 2.

• A second detection layer, not more investigation tooling. Plan 2’s additions are Threat Explorer, AIR, hunting and simulation. Sentaro’s Message vector reads intent, sender identity, thread context and QR-code destinations on every inbound and internal message, and treats payload-free BEC and vendor compromise as a core design target.
• OAuth and shadow AI in the same platform. Neither plan includes OAuth app governance (Microsoft sells it as Defender for Cloud Apps). Sentaro’s App vector inventories every app, AI tool and OAuth grant within 15 minutes of connecting, with one-click revocation.
• Fast to try, no mail-flow change. Sentaro connects over API in four minutes; no MX changes, no agents; historical visibility within 15 minutes.
• One published price. $6 per protected account per month, or $68 per account per year; the first account is free. Every feature is included. Prices in USD.
• Google Workspace too. If part of your organization runs Google Workspace, the same Sentaro deployment covers it; Defender for Office 365 does not.
• EU hosting. Hosted in Sweden on Microsoft Azure; subprocessors are listed in the DPA (/en/legal/dpa).

Be clear about the trade-offs. Sentaro is not part of Microsoft’s ICES Vendor Ecosystem, so its verdicts appear in its own console, not in the Defender portal. Sentaro has no live account-takeover or identity detection yet (see the roadmap note). If you need Microsoft-native hunting across Defender XDR, Plan 2 remains the tool for that, and Sentaro can still run beside it.