Germany's 1&1 has migrated all of its mobile customers onto its 5G open RAN network, completing a switchover that makes it the first major European operator to run its entire retail base on a vendor-split radio architecture.

The milestone, reported by Light Reading, closes a chapter in one of Europe's most closely watched network experiments. 1&1 — Germany's fourth-largest mobile operator, controlled by United Internet — chose open RAN as the foundation of its 5G build rather than the single-vendor stacks that dominate the German market. Rivals Telekom, Vodafone and O2 Telefónica all rely on conventional integrated radio platforms.

What does the migration actually cover?

The word "all" carries weight here. Every 1&1 mobile customer now sits on the open RAN-based 5G core and radio network, not a hybrid of legacy and new platforms. That matters because operators elsewhere in Europe have deployed open RAN in pockets — rural clusters, campus networks, single towns — while keeping the bulk of traffic on conventional kit. 1&1 is claiming something broader: a full base, nationwide.

The commercial reality is more layered than the headline suggests. 1&1 spent years as a virtual operator, selling service that ran as an MVNO on O2 Telefónica's network while it built its own infrastructure. Completion of the customer migration means its subscribers now ride on 1&1's own open RAN assets — but roaming and national roaming arrangements have historically remained part of its coverage story where its own sites have not yet reached. The company has not, in the reporting available, detailed how much traffic still depends on a host network rather than its own antennas.

Why Germany's regulator liked this plan

1&1's open RAN commitment was not purely a technology bet. It won conditional backing from Germany's Federal Cartel Office, which pushed the 2020 spectrum auction toward outcomes that would weaken the hold of the three incumbent network owners. Open RAN, which separates the radio unit from the intelligent software baseband layer and lets operators mix suppliers, was the policy instrument for that goal.

The technology argument is straightforward: interoperability should, in principle, let a challenger buy best-of-breed components and avoid lock-in to Ericsson, Nokia, Huawei or any single vendor. Whether that translates into lower total cost of ownership at scale remains unproven across the industry — several early open RAN deployments outside Japan have been quietly re-tendered or absorbed back into single-vendor deals.

The vendor line versus the deployment line

Vendor marketing around open RAN tends to emphasise flexibility and future-proofing. The deployment record is thinner. Rakuten Mobile in Japan built a nationwide open RAN network and then struggled with coverage costs that helped push the business into sustained losses. 1&1, which signed Rakuten's network unit as a key integration partner, inherited both the architecture and the cautionary tale.

What 1&1 has now demonstrated is that the model can carry a full national customer base in a mature European market — a proof point no other operator of comparable scale on the continent can claim. What it has not yet demonstrated, publicly, is unit economics: capex per site, network quality metrics against the incumbents, or churn among customers moved onto the new platform. Those numbers, when they appear in United Internet's financial reporting, will do more to validate open RAN in Europe than the migration announcement itself.

What comes next

The migration completes the customer side of the project, not the network side. 1&1's remaining task is densification — extending its own site footprint so that dependency on host-network capacity continues to shrink. That rollout timeline, and the investment behind it, will decide whether Germany's open RAN pioneer ends up as a template for Europe's next network builds or a single, well-documented exception.