Eurostar saw a 24% rise in US travellers and an 18% rise in other non-European customers during the first half of the year.
The cross-Channel train operator said they were drawn by the weaker pound, which has increased their spending power.
Eurostar said there was also a strong business travel market, which was up 5% in the first six months of 2017. UK business traffic was up 7% year-on-year.
Sales revenues grew to £452.6 million, a 6% year-on-year increase at constant exchange rates.
Passenger numbers were up by 1% to 5.04 million.
Chief executive Nicolas Petrovic said: "We have recorded good growth in the first six months of the year with a marked increase in traffic from the US and overseas markets.
"This is testament to the enduring popularity of our destinations combined with favourable exchange rates. The outlook for the second half is promising with a busy summer season and bookings for the autumn up on last year".
