Migrating Azure ExpressRoute Gateway

Introduction

Microsoft has announced the retirement of the Basic IP SKU and Legacy Gateways, effective 30 September 2025. If your environment is using the legacy ExpressRoute Gateway, this article guides you to help you streamline the transition and avoid unnecessary workloads.

The following scenarios apply to ExpressRoute Gateway migrations.

• Basic Public IP SKU Gateway.
• Non-Az-enabled SKU on Standard.

Step 1. Go to the ExpressRoute Gateway and Select Gateway SKU Migration under the Settings.

Step 2. Click Validate to verify if the Gateway is ready for migration.

A list of prerequisites will be displayed, outlining the conditions that must be met before starting the migration.

Note. If any prerequisites are not met, the validation will fail, preventing you from proceeding.

Solution. Recreate the ExpressRoute Gateway with the Standard IP.

Step 3. After successful validation, we can proceed to the Prepare stage. At this stage, a new Virtual Network gateway is created.

In the Virtual Network Gateway Details section, provide the following information.

• Gateway Name
• Gateway SKU
• Public IP Address

Select Prepare to create the new ExpressRoute Gateway. This operation could take up to 15 minutes.

Step 4. After successfully provisioning the Gateway, we will notice that the new Gateway is provisioned within the Resource Group.

Step 5. Navigate to the existing ER Gateway, click on Gateway SKU Migration, and confirm that the Prepare operation has been completed. You can now proceed to migrate your traffic to the new ExpressRoute Gateway.

Step 6. Select the New Gateway under Migrate Traffic and click the Migrate Traffic Button.

Step 7. Once the traffic migration is complete, you will move to the Commit stage. In this stage, the migration is finalized by deleting the old Gateway. To proceed, select Commit Migration. This final step is designed to ensure there is no downtime.

Type Yes, and Click Commit.

Summary

When migrating the ExpressRoute Gateway, there may be a brief service interruption lasting between 30 to 60 seconds. To minimize the risk of unnecessary escalations, it is advisable to request a 15-minute downtime window from the customer before initiating the migration process. If you need further consultancy, reach out to me.