It will be August at the earliest before international travel resumes, according to the Tánaiste.
The EU's Green Travel Cert system may be ready by June, but Ireland will take some time to fully sign up to it.
Tomorrow a memo will go before Cabinet Ministers outlining the planned easing of restrictions on international travel over the coming months.
Speaking today, Mr Varadkar warned they will still take a cautious approach.
He said: "Realistically, I think it's towards the end of the summer.
"It's more likely to be around August at the earliest before we say to people it's OK to engage in non-essential travel."
The EU's green cert travel scheme is due to be announced in mid to late June.
It's aimed at allowing travel resume within the bloc, with a digital pass showing whether someone has been vaccinated or tested negative for COVID-19.
However, the Tánaiste says Ireland may not sign up straight away.
He noted: "Member states will have six weeks to adopt it - that is the period between the middle of June and early August, during which member states can adopt it."
Mr Varadkar also said it's his firm ambition that restrictions on movement within the common travel area with the UK will be lifted very soon.
People arriving here from the UK currently have to quarantine at home for 14-days, although the quarantine can end earlier if they have a negative PCR test five days after arrival.
Tomorrow Cabinet will also discuss the future of mandatory hotel quarantine, which the Tánaiste says will be with us for some time to come.