Monaghan and Longford are two of only four walk-in Covid-19 vaccination clinics operating in the country today.
The other two are located in Dublin, in Croke Park and Swords.
In Monaghan the clinic is in the Glencarne Hotel in Castleblayney and will be open between 8.30am and 7.30pm today.
While the Longford walk-in vaccination centre will operate between 9am and 1pm today in Newtownforbes.
They're for over-16s who want a first dose of a Pfizer jab.
Former head of the HSE, Tony O'Brien, is urging people to avail of the opportunity to get a vaccine.