Deutsche Telekom is connecting 5,000 Telefónica Deutschland base stations to its fibre network as both German operators look to expand.
By connecting Telefónica Deutschland to its fibre network, Deutsche Telekom said it would benefit from synergies. It will be responsible for operating and monitoring the network.
Both operators said the partnership would also pave the way for upgrading the 3G and LTE antennas at the base stations to 5G during the coming years.
The agreement builds upon a longstanding partnership dating back to 2011 when the telcos signed a mobile backhaul tie-up.
Earlier this summer, Telefónica Deutschland began its fibre network expansion by working with fixed line provider NGN Fiber Network to connect at least 1,500 sites.
Dirk Wössner, Managing Director of Telekom Deutschland, described the agreement as an important step in securing the future of Germany's mobile infrastructure.
He said: "Everyone will win from this cooperation, because Deutsche Telekom and Telefónica can both capture synergies.
"The resources that we save will be dedicated directly to our own network upgrades and the development of 5G."
Markus Haas, CEO of Telefónica Deutschland, added: By using the available infrastructure, we can accelerate the expansion of our mobile network and get a significant portion of our mobile base stations in shape for the future 5G standard. As a result, our customers will benefit directly from a more powerful mobile network and a better user experience."
Fibre competition in Germany is increasingly fierce with Vodafone Germany also planning to upgrade its network to offer speeds of 1GBps by the end of 2020.
Meanwhile, Deutsche Telekom also announced this morning it had completed the latest stage of its fixed line upgrade, bringing speeds of up to 1,060 coastal areas.