The European season kicks off this weekend with an even split of Irish provinces taking part in the Investec Champions Cup and Challenge Cup.
Four-time champions Leinster start their latest bid for glory with a home tie against Harlequins, while 2006 and 2008 winners Munster visit Bath.
Ulster welcome Racing 92 to Belfast on Friday night in the Challenge Cup, while Connacht head to Wales to take on Ospreys on Sunday afternoon.
Find out all you need to know about the games here.
TV
The four games will be shown live on Premier Sports.
RADIO
There will be live commentary of Bath v Munster on RTÉ Radio 1's Saturday Sport.
ONLINE
We'll have live scoring, reports and reaction from all the province's games.
WEATHER
Belfast is set for heavy rain that should ease off around kick-off and a moderate breeze in about 9C for Friday night's Ulster v Racing Challenge Cup opener, while light drizzle is forecast in Dublin on Saturday evening for Leinster v Quins.
There's a light breeze and light rain expected in Bath on Saturday night for Munster's visit with temperature around 9C.
It's a similar outlook for Connacht's game in Swansea on Sunday afternoon.
Last year's beaten semi-finalists Leinster enter the European fray after a disappointing domestic start in the URC.
They have suffered three defeats from six games and can consider themselves lucky to have emerged from last weekend's clash at Dragons with five points.
Leo Cullen's side, who also host La Rochelle and meet Leicester and Bayonne away in Pool 3, have been hit hardest by British and Irish Lions and Ireland commitments but they will still have expected more of themselves given their strength in depth.
The teams met as recently as last season's Round of 16 clash when Leinster hammered Quins 62-0 at Croke Park.
The English side, under head coach Jason Gilmore, are eighth in the Premiership with just two wins from six games and lost 26-15 away to Gloucester last weekend.
Caelan Doris returns to the Leinster side for the first time since his shoulder surgery last May, while Rieko Ioane is in line for his debut off the bench.
Leinster: Jimmy O'Brien; Tommy O'Brien, Garry Ringrose, Ciarán Frawley, Jordan Larmour; Sam Prendergast, Jamison Gibson-Park; Paddy McCarthy, Dan Sheehan, Thomas Clarkson; RG Snyman, Joe McCarthy; Jack Conan, Josh van der Flier, Caelan Doris (capt).
Replacements: Rónan Kelleher, Jack Boyle, Tadhg Furlong, Diarmuid Mangan, Max Deegan, Luke McGrath, Harry Burne, Rieko Ioane.
Harlequins: Midday
Referee: Craig Evans (Wal)
Munster had their early-season momentum halted with a 27-21 loss to URC table-toppers Stormers last weekend.
Prior to that, Clayton McMillan's side had won five from five, including a fine victory away to champions Leinster.
They host Gloucester at Páirc Uí Chaoimh next weekend and are away to Toulon and home to Castres after Christmas in Pool 2.
Beaten by eventual champions Bordeaux in the quarter-finals last season, Munster will aim for a better pool performance this time around to gain a better knock-out route.
They beat Stade and Saracens at home but lost narrowly away to Castres and Northampton, who reached the final.
Bath, under former Munster head coach Johann van Graan, won the Premiership and the Challenge Cup last season and have five wins from six in the English league to date, including last weekend's 36-29 victory at Saracens.
Teams: Midday
Referee: Jeremy Rozier (Fra)
After a 14th-place finish in last season's URC table, Richie Murphy's side face into a maiden full Challenge Cup campaign having missed out on the top tier for the first time.
They scraped through to the knockout stages of the Champions Cup last season with one pool win before losing to Bordeaux in the round of 16.
They welcome Racing 92 to the Affidea Stadium off the back of a fine run of four wins from five URC games, including last weekend's bonus-point win over Benetton.
Pool 3 also sees away ties against Cardiff and Cheetahs before Stade come to Belfast in round four.
Racing 92, who reached the semi-finals last season after dropping down from the Champions Cup, are 11th in the Top 14 with six wins from 11 games.
Australia international prop Angus Bell is in line for his Ulster debut off the bench.
Ulster: Jacob Stockdale; Rob Baloucoune, James Hume, Jude Postlethwaite, Zac Ward; Jack Murphy, Nathan Doak; Sam Crean, Rob Herring, Tom O'Toole; Harry Sheridan, Charlie Irvine; David McCann, Nick Timoney (capt) Juarno Augustus.
Replacements: Tom Stewart, Angus Bell, Scott Wilson, Joe Hopes, Bryn Ward, Conor McKee, Jake Flannery, Stewart Moore.
Racing 92: Geronimo Prisciantelli; Nolann Donguy, Sam James, Vladi Ashvetia, Wilfried Hulleu; Antoine Gibert, Kleo Labarbe; Edouard Jabea Njocke, Yanis Basse, Gia Kharaishvili; Junior Kpoku, Will Rowlands (capt); Fabien Sanconnie, Noa Zinzen, Lekima Tagitagivalu.
Replacements: Diego Escobar, Herman Coetzee, Lehopoame Leota, Maxime Baudonne, Jonny Hill, Auguste Albuisson, Leo Carbonneau, Arthur Espeut.
Referee: Ben Breakspear (Wal)
Connacht finished last season in 13th place and so get another spin in the Challenge Cup. Last year they won all four pool games and a knockout tie before losing at home to Racing in the quarter-finals.
They've had a mixed start to life under new head coach Stuart Lancaster, winning two of five URC games but will be buoyed by last weekend's handsome 44-17 victory over the Sharks in Galway.
They host Black Lion from Georgia and French side Montauban later in Pool 1, while they travel to Montpellier in round three.
The Westerners have also been hit with an injury set-back with the news that star back Mack Hansen is out for the medium term.
The Ospreys won four of six games in the competition last season, losing their quarter-final to eventual finalists Lyon.
Domestically, the Welsh region, under head coach Mark Jones, sit in 13th with just one victory, against Zebre, from six ties.
Teams: Friday afternoon
Referee: Evan Urruzmendi (Fra)
Elsewhere, defending champions Bordeaux-Begles start off their campaign away to Bulls and Ronan O'Gara La Rochelle host Leicester Tigers in the pick of the ties.
You can see the full list of fixtures, results and standings for the Champions Cup here, and the Challenge Cup here.
Listen to the RTÉ Rugby podcast on Apple Podcasts, Spotify or wherever you get your podcasts.
