Microsoft 365 E3: Enterprise Plan Features & Pricing

If you run IT for a growing UK business and you are weighing E3 against Microsoft 365 security on a Business Premium licence, this guide gives you the practitioner answer: what E3 actually adds, what it leaves out, and the scenarios where paying nearly double per user pays for itself.

What is Microsoft 365 E3?

Microsoft 365 E3 is the first tier in Microsoft's Enterprise (E) range. It bundles the full desktop Office suite, Windows 11 Enterprise, Exchange, SharePoint, OneDrive, Teams, identity controls and a layer of compliance tooling into one per-user licence. It is built for scale and governance rather than small-team simplicity.

The plan is technically available from a single user, but the feature set is aimed at organisations that have outgrown the Business tier's 300-seat cap or need retention and discovery controls the Business plans cannot offer. UK cloud adoption has driven this shift — total UK IaaS and PaaS revenue reached £9 billion in 2023, up from £3.8 billion in 2020 at an average of 33% per year (UK government data, 2023).

What is included in Microsoft 365 E3?

E3 covers four areas: productivity apps, identity and access, compliance, and baseline security. It includes everything most knowledge workers touch daily, plus governance features that smaller plans omit. The headline differences from Business Premium are unlimited Office installs, larger mailboxes and Windows 11 Enterprise.

Productivity applications

• Installed Office desktop apps — Word, Excel, PowerPoint, Outlook, OneNote, Access, Publisher — with unlimited installs per user (Business plans cap this at five devices)
• Office mobile and web apps
• Microsoft Teams for meetings, chat and collaboration
• Exchange Online Plan 2 — 100GB mailbox, in-place archiving, litigation hold
• OneDrive for Business — 1TB per user
• SharePoint Online Plan 2

Identity and access management

• Microsoft Entra ID P1 (formerly Azure AD Premium P1) — conditional access policies, risk-based sign-in and group-based access management
• Self-service password reset with on-premises writeback, hybrid join and enterprise state roaming

Compliance and information protection

• Microsoft Purview compliance tooling
• Litigation hold and in-place archive
• eDiscovery across Exchange, Teams, SharePoint and OneDrive
• Audit logs with extended retention
• Microsoft Information Protection P1 — sensitivity labels and basic DLP

Security

• Microsoft Defender for Office 365 Plan 1 — Safe Links, Safe Attachments, anti-phishing
• Windows 11 Enterprise E3 with Autopilot zero-touch deployment
• Microsoft Intune device management for endpoints and apps

You can verify the full licence breakdown on Microsoft's official Microsoft 365 plans page and the technical detail on Microsoft Learn.

How does E3 compare to Business Premium and E5?

Business Premium and E3 overlap heavily, but E3 adds enterprise governance and Windows Enterprise, while E5 layers on advanced security and built-in voice. Choosing well means matching the plan to your compliance obligations and scale, not to a feature checklist. The table below sets out the practical differences.

Business Premium remains the sweet spot for most UK SMEs under 300 staff that want strong security without enterprise governance. The Microsoft 365 Business Premium licence list price is £16.90 per user per month (ex VAT, annual) per Microsoft UK. E3 earns its place when retention, discovery or Windows Enterprise become hard requirements.

What does Microsoft 365 E3 not include?

E3 is comprehensive but not complete. The most common gaps that catch buyers out are advanced endpoint security, built-in phone calling, and the higher-tier identity protection found only in E5. If any of these are non-negotiable, budget for add-ons or step up to E5.

• Microsoft Defender for Endpoint Plan 2 — advanced EDR is E5 or an add-on. For managed detection beyond E3, see Microsoft Defender for Business
• Teams Phone System — PSTN calling needs an add-on or Calling Plan; for full voice see Microsoft Teams calling
• Teams Audio Conferencing — dial-in by phone requires an add-on
• Microsoft Purview advanced compliance — insider risk management and advanced eDiscovery
• Entra ID Premium P2 — Privileged Identity Management and Identity Protection
• Power BI Pro

E3 also has no native long-term protection against accidental deletion or ransomware in the cloud — Microsoft operates a shared-responsibility model, so independent Microsoft 365 backup remains your responsibility, not Microsoft's.

When should a UK business choose E3?

Choose E3 when governance and scale outweigh cost. It is the right baseline for organisations that must retain and discover data for legal or regulatory reasons, run large device estates, or need Windows 11 Enterprise and Autopilot. For standard security needs under 300 users, Business Premium usually wins on value.

E3 makes sense for organisations that:

• Have 300-plus users, above the Business plan cap
• Require litigation hold and eDiscovery for compliance, legal or sector obligations (financial services, legal, healthcare, public sector)
• Run a large, device-heavy workforce needing unlimited Office installs
• Standardise on Windows and want Enterprise security plus Autopilot deployment

The NCSC's guidance on access control and identity hardening applies whichever plan you land on — see the NCSC for current UK best practice. Before you commit, a Microsoft 365 security audit tells you whether your current licence is already leaving gaps you are paying to fix at the wrong tier.

How AMVIA helps you license the right tier

Most over-spend on Microsoft licensing comes from buying a tier for one feature and ignoring cheaper paths to the same outcome. AMVIA's approach is to map your compliance obligations, device estate and security posture first, then recommend the plan and any add-ons that meet them — one provider, security-first, Microsoft-certified.

That often means Business Premium plus a targeted add-on rather than a blanket E3 rollout, or E3 for a regulated subset of users and Business Premium for the rest. We configure conditional access, Intune and Defender properly whichever tier you choose, so the licence you pay for is actually doing its job.