Cosmote S.A.

Cosmote Telekom, known as just Cosmote, is the largest mobile network operator in Greece and it is a division of the Hellenic Telecommunications Organization (OTE), the incumbent telecommunications provider in Greece.

Cosmote also operates in Romania as Telekom Romania. As of October 2024, the company is attempting to sell the operation with talks ongoing with Vodafone Romania and Digi.

Previous operations included GLOBUL in Bulgaria (now Yettel) and Telekom in Albania (now One Albania).

In September 2015, OTE Group announced plans to adopt the COSMOTE brand as their uniform commercial brand covering fixed, broadband and mobile telephony (previously fixed and broadband services were sold under the OTE brand). This was in contrast to adopting the Deutsche Telekom brand which the OTE Group had done with its operations in Albania and Romania.

Since 2023, there has been activity to raise awareness of the T brand in Greece. In September, after the T logo was added to the OTE Group building in Athens, the chief of Deutsche Telekom hinted that the T logo may be adopted

The website, stationary and printed advertisements and billboards now feature the T logo in addition to Cosmote with the statement "Member of T Group".

Television and radio advertisements now use the slogan "Cosmote, member of the Telekom Group" with splash screens of the T logo appearing at the end of TV commercials. Cosmote also have introduced "Powered by T" for selected programs and competitions such as Women in Gaming and World Pass.