Rory Best, Iain Henderson and Rob Kearney have signed new IRFU deals in the wake of Ireland's Grand Slam success on Saturday.
Ulster hooker Best and Leinster full-back Kearney have extended their contracts to the 2019 World Cup.
Versatile forward Henderson has agreed a three-year extension to keep him at Ulster until at least June 2021.
"I feel I can continue to make a contribution to both Ireland and Ulster Rugby," said Ireland captain Best.
"I'm delighted to have extended my contract to the next World Cup."
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Under his stewardship Ireland recorded their first win over the Springboks on South African soil as well as clinching a first ever victory over New Zealand in Chicago in 2016.
Best secured his second Grand Slam success by leading Ireland to a 24-15 victory England at Twickenham on Saturday.
Best, 35, and Kearney are the only two Ireland players to feature in both the 2009 and 2018 Grand Slams.
Kearney made his Ireland debut against Argentina in June 2007 and has won 83 caps, scoring 13 tries and a conversion.
He started every match of the successful 2014 and 2015 championship campaigns as well as every game of the 2009 and 2018 Grand Slam seasons.
The two-time Lions tourist (2009 & 2013) has won three Heineken Cups with Leinster and was ERC Player of the Year in 2012.
"I am delighted to have extended my IRFU contract and look forward to continuing to achieve with this Ireland squad," said the 31-year-old.
"There have been some fantastic days for both Ireland and Leinster over the course of my career and there is huge potential for growth in both squads as we look to build and develop and challenge for honours."
Henderson has amassed 38 caps for Ireland since his debut against South Africa in November 2012.
The 26-year-old started all three Tests in the victorious 2016 Summer Tour of South Africa and played in four games during this season's Grand Slam triumph.
"The Irish rugby set up is one of the best in world rugby," said Henderson.
"Since turning professional I have been able to develop in an environment that has seen both provincial and national teams being part of some fantastic days and indeed some challenging times over the past seasons."