The strikes were called after the UK Government turned down its offer of formal detailed negotiations as an alternative to industrial action.
Nurses will strike across England, Wales, and Northern Ireland, with RCN sharing the exact NHS employees that will be striking next week.
In Scotland, the RCN has paused announcing strike action after the government there reopened NHS pay negotiations.
"Ministers have chosen strike action. They have the power and the means to stop this by opening serious talks that address our dispute."
Members in England, Wales & Northern Ireland will take strike action on 15 & 20 Dec.
— The RCN (@theRCN) November 25, 2022
Previously, the RCN said that nursing staff at the majority of NHS employers across the UK had voted to take strike action over pay and patient safety.
Adding that despite a pay rise of around £1,400 awarded in the summer, experienced nurses are worse off by 20% in real terms due to successive below-inflation awards since 2010.
RCN General Secretary Pat Cullen said: “Ministers have had more than two weeks since we confirmed that our members felt such injustice that they would strike for the first time.
“My offer of formal negotiations was declined and, instead, ministers have chosen strike action. They have the power and the means to stop this by opening serious talks that address our dispute.
“Nursing staff have had enough of being taken for granted, enough of low pay and unsafe staffing levels, enough of not being able to give our patients the care they deserve.”
The RCN added that the economic argument for paying nursing staff was clear, as billions of pounds are being spent on agency staff to fix the workforce gaps.
Sharing that in the last year, 25,000 nursing staff around the UK left the Nursing and Midwifery Council register, with poor pay contributing to staff shortages across the UK, which it warned was affecting patient safety.
Currently, in England alone, there are 47,000 unfilled registered nurse posts, according to the RCN.