Accounts filed at Companies House show turnover rose 9% from £37.3 million to £40.8m in 2012.
However a £5m rise in operating charges to £33.16m resulted in pre-tax profits at the Glasgow company, which has its registered office at Buchanan Bus Station, falling from £7.5m to £5.7m.
Separate documents at Companies House show Sir Brian Souter stepped down as a director from Scottish Citylink in June this year just a few weeks after he moved from chief executive to chairman at Stagecoach.
Stagecoach's current chief executive, Martin Griffiths, remains as a director at Scottish Citylink.
Writing in the accounts for 2012 the directors said they were pleased with the performance in the year and added the "outlook for the foreseeable future is satisfactory".
A dividend of £5m was proposed and paid after the year end, up from the £3.5m paid out for the previous year.
Average staff numbers in the year grew from 80 to 95 with employee costs rising from £1.64m to £1.87m.
The net funds position improved from £3.05m to £6.65m.
At the year end Citylink was due almost £8m from Stagecoach but owed the Perth company £5.6m.
In July this year Citylink launched the first direct bus link between Glasgow city centre and Edinburgh Airport.
ComfortDelGro Corporation is one the world's largest transport companies with a fleet of more than 46,000 vehicles across Ireland, the UK, Australia, Malaysia, Vietnam and Singapore.