The city and county of Dublin has been moved to Level 3 of the Government's Living with Covid plan.
Taoiseach Micheál Martin confirmed the new restrictions, which took effect from midnight, will last for three weeks.
Here's what that means for the 1.4 million people who live in the Dublin area:
Those living in Dublin are advised to stay within the county unless they have to travel for work, education and other essential purposes.
People from outside Dublin are advised to only travel into the county for these same essential purposes.
This applies to Dublin residents who want to fly out of Dublin Airport as they should only do so if their journey is essential.
Asked about how this will be policed, Micheál Martin said there will be increased presence of gardái. "They will make a judgment call, as they do already every day," he said.
Eamon Ryan later said that the regulations would be enforced by the gardaí and the airport authorities. "They will be using their discretion," the Minister for Transport said.
A spokesperson for the daa, the operator for Dublin and Cork airports, said airport authorities have no access to any personal passenger information.
Visitors to private homes, including gardens, are allowed from one household and only up to a maximum of six people.
No organised indoor gatherings are allowed (this includes cinemas and theatres).
Organised gatherings (example, sports training) outdoors are allowed but with a limit of 15.
The rules for meeting in a public park remain the same as when you meet in your own garden, only interact with one other household and only up to a maximum of six people.
You can literally dine out - as in, only outdoors. There will be no indoor dining in restaurants and gastropubs in the capital for the next three weeks.
However, they can stay open for takeaway and delivery only or serve food to a maximum of 15 customers outdoors.
They will not be allowed reopen for at least the next three weeks.
Supermarkets and other retail outlets
They remain open with protective measures.
They remain open but can only provide services to guests staying there. Non-residents cannot eat in hotel restaurants, for example.
Sports training can continue but only outdoors and in pods of up to 15. Individual training can take place indoors but no classes. So that means any group activity in gyms etc is not allowed.
No matches can take place.
There will be exemptions for elite sports (professional sports people, inter-county GAA, horse-racing behind closed doors etc)
Weddings will have a cap of 25 guests from Monday, but any weddings due to take place tomorrow and Sunday can go ahead with 50 attendees.
Confirmations and Communions are cancelled as all indoor gatherings are banned.
Religious services will be online only. Funerals will be limited to 25 mourners.
Places of worship remain open for private prayer.
Schools and childcare services will remain open with protective measures.
Third Level learning will move online, in as far as is practicable.
Visits to long-term residential care facilities are suspended apart from on compassionate grounds - if a relative is critically ill, for example.
Over 70s and medically vulnerable
The advice is to stay at home as much as possible and limit your social contacts.
Use only if essential, walk or cycle as much as possible.
Work from home as much as possible.
There will be €30m in grant aid for businesses in Dublin through a 30% increase in the restart grant.
There will also be €5m allocated for culture, tourism and sport in the capital.
Commercial rates, VAT and the wage subsidy scheme will be examined in the Budget, according to Tánaiste Leo Varadkar.