• Optimum expanded its multi-year agreement with T-Mobile to add access to the carrier's standalone 5G network and support more connected devices
  • Optimum will connect its own mobile core to T-Mobile's 5G platform, with the full service expected to launch in early 2027

The fact

Optimum Communications said on 31 August that it had expanded its multi-year mobile agreement with T-Mobile. The deal will give Optimum customers access to T-Mobile's standalone 5G network, support more smartphones, wearables and other connected devices, and improve domestic and international roaming. Optimum had surpassed 700,000 mobile lines before announcing the expanded agreement.

Optimum sells mobile service using T-Mobile's nationwide wireless network rather than building a national network of towers and radio equipment itself. It is not, however, simply reselling the entire network. Optimum operates its own mobile core, the systems that manage customer connections and network services, at four locations in the US. It is now integrating that core with T-Mobile's standalone 5G platform.

The integration is expected to begin rolling out this year, with a full launch planned for early 2027. Many existing Optimum Mobile phones should move across without any action from customers, although some devices will require a migration plan. Financial terms of the agreement were not disclosed.

The assessment

The agreement moves Optimum's next mobile upgrade into network integration rather than a national radio build. Optimum already operates its own mobile core, so the new work is to connect that infrastructure with T-Mobile's standalone 5G platform and move customers onto the combined service.

That division leaves the two companies responsible for different parts of the network. Optimum manages its core, subscribers and retail service, while T-Mobile provides the nationwide radio network and the 5G platform carrying the additional functions. Optimum can decide how to package those services, but features provided through T-Mobile still depend on the host network.

For BTW readers, the deal draws a clear boundary around Optimum's full-MVNO model. It can control its mobile core and retail products without owning a national radio network, but adding T-Mobile's newer 5G functions still depends on the two networks being integrated and kept compatible.

What to watch

Watch for Optimum to begin customer migration in 2026 and complete its full standalone 5G launch in early 2027. Wider support for wearables and other devices, expanded roaming and the planned small-business mobile packages in the first half of 2027 will provide concrete evidence of which new functions have moved into customer service.