Anyone over 18 can register for a Pfizer or Moderna Covid-19 vaccine from today.
The HSE's online portal is now open for all adults - allowing them to sign up for an mRNA jab.
Health Minister Stephen Donnelly says this is happening because the vaccination programme is ahead of schedule.
Former head of the HSE, Tony O'Brien, says the rollout is going well.
"I think we're now vaccinating at a faster rate than any of the other EU countries - very impressive.
"Today is another really important step. We know that the unvaccinated under 30s seem to be at particularly high risk from the Delta variant, they've had access to Jansen from pharmacies in recent times and now this option too.
"I'd encourage everyone who is now eligible to look for a vaccine if they've not already had one."
You can register for the Covid-19 vaccine at https://vaccine.hse.ie
