Members of the RMT union are on strike from August 12-15, and August 27-29 over the bank holiday weekend, the BBC said.
Staff that are part of the TSSA plan to strike on August 14 and 15, and August 28 and 29.
Eurostar said it had subsequently made some modifications to its weekend timetable.
Eight services have been cancelled, but the company said the changes would enable “all passengers to be able to travel”.
A Eurostar spokesperson added: "We are aware of the plans for strike action and our focus has been seeking a joint resolution while planning to provide a good service for our customers."
