The recruitment drive has been launched after director of corporate affairs Debra Aspin confirmed she will not return to work after maternity leave.
Aspin had held Eurostar's top communications job since 1996 and went on maternity leave more than a year ago.
Since then the nine-strong comms department has been overseen on an interim basis by Roya Nasser, set to return to freelance work when a permanent appointment is made.
Senior press officer Roger Harrison confirmed that a recruitment process was underway but declined to disclose whether a shortlist of candidates had been drawn up.
Harrison said Eurostar had used PR agencies on an ad hoc basis in the past, adding the company was not working with any external PR firms.
Eurostar hit the headlines earlier this month when around 600 passengers were stranded for five hours on a broken-down train outside Waterloo station and smashed windows to ventilate carriages.
The company began operating in 1994 and runs trains from London to Lille, Paris and Brussels via the Channel Tunnel.