Can we add Teams calling to an existing GCC High environment?

Teams calling can be added to an existing GCC High tenant without migrating to a new environment. The process layers Direct Routing voice services on top of the current Microsoft 365 GCC High deployment, keeping all existing configurations, users, and data intact.

Adding Teams calling requires three things: Teams Phone licenses for each user who will make or receive calls (included with E5 GCC High or available as an add-on for E3 GCC High), a compliant Direct Routing provider to manage SBC infrastructure and PSTN connectivity, and configuration of call routing, dial plans, and emergency calling within the Teams Admin Center. The provider handles the SBC deployment and PSTN trunk connection on their end, while the organization's IT administrator assigns phone numbers and calling policies through the existing GCC High management portal. No on-premises hardware is required when using a managed DRaaS provider. The integration connects seamlessly with existing Microsoft 365 GCC High applications including SharePoint, Exchange, OneDrive, and Outlook.