One Montenegro, legally known as One Crna Gora DOO, operates as a mobile phone service provider in Montenegro. The company's inception traces back to November 1995 when PTT of Montenegro and European Telecom Luxembourg agreed to establish a limited liability company to secure a mobile telephony license in Montenegro. This partnership led to the creation of ProMonte in March 1996, which began operations in July the same year. ProMonte transitioned its ownership to Telenor in 2004, becoming a wholly-owned subsidiary of the latter.
In 2018, Telenor's Southeast Europe business, including Telenor Montenegro, was sold to the PPF investment fund. As of 2021, the company is part of 4iG, following its acquisition from PPF. Ownership was subsequently transferred to Antenna Hungária. In March 2022, the company underwent a rebranding, changing its name from Telenor to 'ONE'. This new brand identity signifies friendliness, commitment, agility, and transparency, reflecting the company's ethos.