Revenue jumped four per cent in the six months to June to £421m. Passenger numbers were up by three per cent to 4.7m.
The number of international passengers rose by 21 per cent, with US custom particularly strong.
The company said the ash cloud crisis had meant more travellers had been forced onto the railway.
Eurostar chief executive Nicolas Petrovic said: "It really helped us because many people tried our service who had never tried it before.
"Our key selling point against airlines is convenience, comfort, and the ability to work on board."