Hairdressers, beauticians, restaurants and pubs that serve food are among the outlets opening today, as phase three of the easing of coronavirus restrictions begins.
It's the biggest reopening since lockdown began on March 12th.
Gyms, swimming pools and other exercise facilities can reopen, while all team sports - including close contact sports - can resume.
Museums, cinemas, theatres, bingo halls, galleries and other cultural outlets have also been given the green light to reopen.
Churches are other places of worship are also allowed to resume services, which many creches and childminding facilities are reopening.
Indoor gatherings will be limited to 50 people for now, while up to 200 people can gather outside.
Social distancing and other health & safety measures will remain in effect across the sectors reopening today.
Face coverings will be compulsory on public transport as capacity increases to around 50% of pre-COVID levels.
While most businesses now have permission to reopen, some will not open their doors immediately - with many cinemas holding off reopening for another few weeks.
Around 40% of pubs are expected to welcome back customers, and those that do not offer 'substantial meals' will remain closed until July 20th.
Customers in both restaurants and pubs that serve food will have to pre-book, and they will be limited to 105 minute visits
Vintners Federation of Ireland Chief Executive, Padraig Cribben, said things will be a bit different in pubs which do reopen today.
He said: "Obviously there will be notifications around the premises in relation to COVID-19... there'll also be elements of hand sanitisation. There'll be a much higher level of table service.
"These are all challenges for publicans - I suppose what is important is that the public plays their part as well."
Meanwhile, some photos shared on social media showed queues outside some barber shops after they reopened their doors at midnight:
Our #dundrum store! pic.twitter.com/BXSC3wgYVd
— The Grafton Barber (@GraftonBarber) June 29, 2020
Masks continue to recommended in retail outlets, and anywhere it is difficult to maintain social distancing.
In Dublin, people are being asked not to take public transport into the city centre at rush hour, as this should be kept for essential workers.
DublinTown and gardaí say the public should stagger the times they take public transport, or cycle or walk when possible.
Health officials are continuing to recommend that people work from home wherever possible.