An Domhain trí Dhathanna, or a world of colour, was the theme of this year's parade in Tralee.
The parade showcased the many nationalities that make up the town's diverse community.
Street performers joined the local floats and participants to add to the excitement there.
A larger-than-life stag was one of the focal points of the parade in Killarney. Named the Monarch of Muckross, it's an echo of Killarney's past, as deer have roamed there for 5,000 years.
And, having rid Ireland of snakes, St Patrick is now helping Killarney Tidy Towns to banish the 23,000 single-use coffee cups used here every year.
The message - bring your own cups.
Meanwhile, the Cork City parade began at 1pm with participants embracing the theme of this year's event - a world of pure imagination. It finished shortly after 2.30pm.
Gardaí estimated over 50,000 people lined Cork city's streets for this year's parade.
The Frank and Walters were this year's Grand Marshals, with the Barrack Street Band accompanying them playing 'After All' - voted the Number One Cork song in recent years.
Lord Mayor Kieran McCarthy took to the street as Willy Wonka, saying the sun came out especially to shine on the 3,500 participants from nearly 60 community groups and organisations who took part.
Among the visitors were a party of 40 from Colonge in Germany to celebrate being twinned with the city for the past 35 years.
There too members of the Knights of Columbus Pipes and Drums Group, who took part in yesterday's New York City parade.
Young Scientist of the year, 17-year-old Sean O'Sullivan, was the Grand Marshall for the parade in Limerick City, while singer Maura O'Connell was Grand Marshall of the Ennis parade.
Additional reporting: Jennie O'Sullivan
