The 'default' limit has now reduced from 80 kilometres an hour to 60 kilometres an hour.
The changes came into effect at midnight last night in an effort to reduce collisions and road fatalities.
Slower speeds are also due to be brought in for built-up areas as well as on national roads later this this year.
People travelling in rural areas from today will see the changes in those speed limits on road signs nationwide.
Irish Coast Guard, RNLI and Water Safety Ireland urge everyone to 'Unite to Turn the Tide
July has been one of the busiest months in years for rescue services, with warm weather bringing more people to Wicklow beaches, rivers and lakes.
Bray Wanderers Head To Cobh Amid Apparent Cross-Channel Interest In Seagulls Talent
New Laws Boost Protection In Wicklow Mountains National Park
A dedicated National Parks Bill will put nature conservation first and help manage growing visitor numbers.
Woman Dies In Waters At Wicklow Beach
The incident occurred on the outskirts of Wicklow town, near the Blainroe golf club.
Wicklow Housing Remains Ireland's Most Expensive Outside Dublin
Strong demand, low vacancy and limited housing stock are keeping county prices elevated.
Sunny intervals
High: 20°C | Low: 13°C
Sunny intervals
High: 20°C | Low: 12°C
Sunny intervals
High: 21°C | Low: 11°C
Light rain
High: 19°C | Low: 12°C
Sunny intervals
High: 20°C | Low: 13°C
