Hellenic Telecommunications Organization

The Hellenic Telecommunications Organization, known as OTE, is a telecommunications provider headquartered in Greece. It delivers a range of telecom services, with its mobile operations being the largest in the country. The organization serves both consumer and business markets across Greece. Its offerings include voice, data, and connectivity solutions.

OTE's mobile subsidiary operates as Greece's largest mobile operator, serving a substantial portion of the population. The company's headquarters are located in Athens, Greece. This position gives it a notable footprint in the national telecommunications landscape. The scale of its mobile network supports widespread coverage across urban and rural areas.

In September 2020, OTE experienced a cyber attack that compromised telecommunications metadata of thousands of customers over a five‑day period. The breach exposed call records such as phone numbers, timestamps, duration, device types, subscriber identifiers, and base station coordinates, though no personal names were accessed. The incident was traced to a third country, with investigators pointing to Lithuania as a likely origin. This event highlighted vulnerabilities in the operator's data protection measures.

As a major telecommunications incumbent, OTE plays a regulatory and infrastructural role in Greece's digital ecosystem. It collaborates with national authorities on network resilience and service continuity initiatives. The organization's longstanding presence has contributed to the development of the country's broadband and mobile infrastructure. These attributes underscore its significance within the Greek telecom sector.