Increased freight and car volumes boosted Irish Continental Group's performance in the first half of the year, with the ferry company's revenue rising 9.5% to €143.1m.
The company, which operates the Irish Ferries brand, said the number of cars it carried on its services in the six month period was 7.1% higher.
Meanwhile the volume of roll-on, roll-off freight was up 11.5%.
This increased income, along with lower fuel costs and favourable changes on the currency markets, resulted in a significantly higher pre-tax profit for the period - up 451.9% to €14.9m.
Net debt fell from €61.3m at the end of December to €33.7m by the end of June.
ICG has set an interim dividend of 3.638 cent per share - up 5% year-on-year.