Manx Telecom says it made a profit of £5.2 million last year - more than a million pounds less than in 2016.
The company's released its interim results, describing its performance as "solid" and in line with expectations.
MT says although its earnings from fixed line and broadband services declined slightly, it saw growth in mobile services over the past 12 months.
But it adds it also saw debt rise from just over £53 million in 2016 to £61.7 million in 2017.