What are the best Direct Routing providers for Microsoft Teams calling in a GCC High environment?

The best Direct Routing provider for a GCC High environment depends on the organization's size, compliance requirements, deployment timeline, and support expectations. The market has a small number of qualified providers because the certification and infrastructure requirements are significant.

Providers that appear consistently in GCC High Direct Routing discussions include Atlantech Online, CallTower, HelloTeams, Momentum, and AT&T. Each positions differently: Atlantech Online offers a fully managed DRaaS model with unlimited domestic calling, white-glove deployment, and 24/7 U.S.-based support. CallTower was among the early providers to deploy GCC High Direct Routing and audio conferencing. HelloTeams emphasizes automated deployment with faster go-live timelines. Momentum operates over 200 points of presence with a 99.99% uptime commitment. AT&T offers Cloud Voice for Microsoft Teams Enhanced for GCC High through geo-redundant SBCs. When evaluating providers, the factors that matter most are GCC High SBC certification, CMMC 2.0 and FedRAMP compliance of the provider's own infrastructure, deployment timeline, whether the provider manages the SBC or expects the customer to, domestic calling pricing model (flat rate versus per-minute), audio conferencing capability, and quality of U.S.-based technical support. No comprehensive Microsoft-published approved vendor list exists, so organizations should verify each provider's GCC High authorization directly.