Thousands of ambulance service workers, including paramedics, will walk out on December 21 in a strike coordinated by three unions.
GMB, Unison and Unite announced strikes that will cover most of the country on the same date.
The day after planned strike action by nurses at many hospitals in England, Wales and Northern Ireland, the resulting stress on NHS services is likely to increase.
Union leaders insisted the government has the power to prevent strikes by reopening wage negotiations.
Sharon Graham, general secretary of United, said: “These strikes are a stark warning. Our members are taking a stand to save our NHS from this government.
“Patients’ lives are already at risk, but this government is sitting on the sidelines, shirking its responsibility to