The strike will “severely affect” the popular international rail service and passengers’ travel plans in the typically busy Christmas holiday period, says RMT.
The security staff, who help keep passengers safe, are contracted out to facilities management company Mitie.
RMT says the workers, “some of whom earn as little as £10.66 per hour” rejected a below inflation pay offer and emphatically voted for strike action with an 81 per cent 'yes' vote.
RMT general secretary Mick Lynch said: “Eurostar security staff are essential to the running of Eurostar, and it is disgraceful they are not being paid a decent wage.
“They work long unsocial hours and a multimillion-pound company like Mitie can easily afford to pay them decently for the essential work they do.
“We do not want to disrupt people’s travel plans, but our members need a pay rise, and this is the only way management will listen.
“I urge Mitie and Eurostar to come to a negotiated settlement with RMT as soon as possible.”
Mitie says it firm offered a 10 per cent pay increase to RMT on Tuesday, which the union is yet to respond to.
A spokesperson for the firm said: “We’re disappointed that RMT has made the decision to undertake industrial action, given we have already offered a significant pay increase and pay negotiations are ongoing. We remain open to continuing these discussions.
“In addition, we recently announced a £10m Winter Support package, designed to help the lowest paid colleagues across Mitie with the rising cost of living.”
They added that they hope services will operate as normal despite the strike, thanks to contingency measures.
“As always, our priority is to ensure that exceptional services are delivered as normal so that passengers are able to continue their journeys with minimal disruption,” said the spokesperson.
Responding to news of the strike, a Eurostar spokesperson said: “We are aware that negotiations between Mitie and the unions are ongoing. If there is any impact on services we will update customers as soon as possible.”
December will also see more than 40,000 RMT members across Network Rail and 14 UK train operating companies strike in the run-up to Christmas in a dispute over jobs, terms and conditions and pay.
Staff will walkout on December 13, 14, 16 and 17 and on January 3, 4, 6 and 7. There will also be an overtime ban from December 18 until January 2, making it more difficult for train companies to finalise timetables.
Other industries across the UK are also being hit by industrial action this winter, as other disputes rumble on between staff, employers and unions.
A series of postal strikes are planned in December, including on Christmas Eve, in one of the longest-running disputes of a year dominated by stoppages.
Civil servants in the Public and Commercial Services union are also due to walkout in mid-December as they start a month of industrial action.
Nursing staff at the majority of NHS employers across the UK have also voted to take strike action over pay for the first time in history.
Meanwhile, last week saw around 70,000 members of the University and College Union (UCU) strike in a dispute over pay, pensions and contracts, in the biggest-ever industrial action to affect higher education, which is thought to have affected around 2.5 million students.
The union warned of escalated action in the new year if the row is not resolved.