Microsoft’s transition of Microsoft Sentinel into the Microsoft Defender portal is already underway. After March 31, 2027, Microsoft Sentinel will no longer be supported in the Azure portal, making Defender its long-term operational home.
For organizations still managing Sentinel through Azure, it’s easy to view the transition as a portal migration with a deadline attached. But that misses the bigger picture.
Microsoft is bringing SIEM, XDR, threat intelligence, automation, and AI-assisted investigation together within a unified security operations experience, changing how SOC teams detect, investigate, and respond to threats.
Instead of asking, “When do we need to migrate?” security leaders should be asking, “What kind of SOC are we building for the future?”
Why is Microsoft Sentinel moving to Defender?
Microsoft is consolidating Sentinel into the Microsoft Defender portal as part of its broader vision for unified security operations.
Sentinel provides cloud-native SIEM capabilities, while Microsoft Defender brings together XDR capabilities and security signals across endpoints, identities, email, cloud applications, and other areas of the environment. Combining these capabilities gives analysts a more connected view of threats with less need to move between separate tools and workflows.
Within the Defender portal, organizations can bring together:
- A unified incident queue
- Threat intelligence and advanced hunting
- Security automation and orchestration
- Microsoft Security Copilot capabilities
Exposure management and security posture insights
What does the Sentinel to Defender transition mean for organizations?
With Microsoft Sentinel support in the Azure portal ending in early 2027, organizations should begin planning their transition well before the deadline.
Moving to Defender can affect incident investigation, alert correlation, automation and playbook functionality, permission management, and collaboration across multiple workspaces or tenants.
Teams that assess these impacts early will be better positioned to plan, adapt, and avoid last-minute surprises as the deadline nears.
What are the benefits of unified security operations?
Security teams are dealing with a growing volume of alerts, signals, tools, and data. When these are spread across separate platforms and workflows, analysts spend valuable time gathering context before they can investigate the threat itself.
Unified security operations help reduce that fragmentation and support:
1. A more complete view of an attack
In the Defender portal, Sentinel incidents can be enriched with Microsoft Defender signals, while cross-domain correlation brings related alerts together into a broader attack story. This gives analysts more context to understand how an attack is connected across the environment.
2. Less context switching for analysts
SIEM and XDR data can be investigated through a unified incident experience, with advanced hunting across Sentinel, Defender, and data lake sources. Analysts spend less time navigating between systems and more time investigating and responding to threats.
3. More automation and AI-assisted investigation
Security Copilot capabilities within Defender support incident summaries, guided response actions, threat hunting, and other AI-assisted workflows. Combined with security orchestration and automation, these capabilities can reduce repetitive work and accelerate investigation and response.
How does Defender combine SIEM and XDR capabilities?
SIEM and XDR have traditionally served complementary but separate roles. SIEM provides broad visibility by collecting and analyzing security data across the environment, while XDR correlates signals across endpoints, identities, email, cloud workloads, and other security domains.
Microsoft’s unified security operations model brings the two together. Sentinel provides SIEM capabilities such as data ingestion, analytics, hunting, and automation, while Defender adds cross-domain detection, investigation, and response. Analysts can work from a unified incident queue and investigate threats using correlated signals and shared context.
Is the transition to Defender simply a migration?
No. Focusing only on what needs to move or be reconfigured can overlook a bigger question: how well does your current SOC model support the way your security team needs to work?
This is a good time to examine where analysts are switching between tools, which workflows and automations are critical, and where AI or automation could reduce repetitive work. It also gives teams a chance to revisit processes that may have evolved around individual tools rather than current security needs.
Approached this way, the transition becomes a chance to modernize SOC operations and build a security program that is better aligned with your organization’s needs.
What should organizations evaluate before moving Sentinel to Defender?
Microsoft has continued to expand the Defender experience, including multitenant and multi-workspace capabilities. However, organizations shouldn’t assume every existing Sentinel workflow will operate the same way after the transition.
Microsoft currently documents differences in how certain automation rules and playbooks behave within Defender. Manually created incidents are also not synchronized with the Defender portal, and organizations using multiple workspaces may need to review how data, automation rules, and workflows are distributed.
This is especially important for organizations with complex SOC architectures, custom automation, or managed security environments.
Before transitioning to Defender, consider:
- How your current security architecture maps to the Defender experience
- Whether incident and investigation workflows will need to change
- How existing automation rules, Logic Apps, and playbooks will function
- Whether roles, permissions, and access models remain appropriate
- How cross-workspace and cross-tenant processes will be managed
- Whether data connectors, integrations, analytics rules, and hunting queries are affected
- How analysts need to prepare for changes to their workflows and responsibilities
The goal is to understand whether your SOC is prepared for the operating model Microsoft is building toward.
Don’t wait for the deadline to define your future SOC
March 31, 2027, may seem far enough away to defer planning, but waiting risks turning the transition into a deadline-driven migration.
Microsoft’s direction is clear: Sentinel, Defender XDR, threat intelligence, automation, and AI-assisted security operations are converging around a unified experience.
Now is the time to evaluate whether your architecture, workflows, governance, and people are ready for that model.
How R3 can help
R3 helps organizations approach the Sentinel to Defender transition with a broader security operations strategy.
We can assess your existing Sentinel environment, identify dependencies and readiness gaps, evaluate how current workflows align with Microsoft’s unified security operations model, and build a transition roadmap around your security objectives.
From planning and architecture through implementation and optimization, R3 can help you modernize your SOC and successfully transition to the Defender experience.
Don’t just plan when to move Sentinel. Start planning what you want your SOC to become.
