A large crowd turned out in Belfast on Sunday as the first four-day festival for St Patrick's Day came to a climax with the annual carnival parade at midday.
Deputy Lord Mayor Tierna Cunningham led the parade along with some very special guests, including little Oscar Knox and his family.
"We're just delighted for a start that the snow has stayed away," she said.
"It's great to see such colour and vibrancy along the streets. It's a really great day out and a lovely family atmosphere.
"We're known for having a bit of craic and fun, and that's what it's about today."
It was followed by a concert at Custom House Square where X Factor singer Amelia Lily performed alongside other acts of traditional music and dancing.
In Downpatrick, the town where the patron saint is reputedly buried, the annual celebrations got underway with a pilgrimage to Down Cathedral and an interdenominational festival service.
Events were also held at Down Arts Centre, including music and craft demonstrations, and activities for children.
Entertainment was provided in St Patrick's Square with UTV's Julian Simmons appearing along with a range of special guests.
A cavalcade of vintage cars made their way through the town shortly after 2pm, before the St Patrick's cross-community carnival parade at 2.30pm.
In the UK City of Culture 2013, Derry~Londonderry's parade at 2pm was the highlight of a packed spring carnival weekend.
This year's parade brought together a mixture of new and seasoned community group performances, carnival groups, tradition and contemporary dance groups and pipe bands along the route.
Also included in the St Patrick's programme was street theatre, music, crafts, drama, dancing and story-telling.
Around 1,000 people paraded in Armagh, as spectators turned out to witness the carnival parade which was themed 'Armagh... It's My Own Irish Home'.
Elsewhere, people lined the streets in Newry to see the city's colourful parade on Saturday.
Cllr John McArdle, Mayor of Newry, said they had been working hard to attract a diverse range of people.
He said: "St Patrick is a saint for all religions, not just a saint for Catholics. So we as a council, are very keen to push that and to encourage everyone to participate."
In the Republic of Ireland, a giant Irish-knit jumper and the world's biggest raggy doll were among the sights and sounds at the annual St Patrick's Day parade in Dublin.
Around half a million revellers formed a sea of green, white and orange as they lined the streets in the capital city for the world-famous event.
Meanwhile, Catherine, the Duchess of Cambridge, presented a bunch of shamrock to the regimental wolfhound mascot of the 1st Battalion Irish Guards during the traditional St Patrick's Day parade in Mons Barracks in Aldershot on Sunday morning.
William, the Duke of Cambridge, attended the parade with his pregnant wife as Colonel of the Regiment.