Pat Lam has handed debuts to academy centre Rory Parata and New Zealand-born flanker Nepia Fox-Matamua for the visit of Newport Gwent Dragons in Galway (7.30).
Parata, 21, will partner the explosive Bundee Aki in midfield with Lam admitting that the youngster had earned his chance off the back of his excellent pre-season form.
Having spent time in Irish camp during the summer, Denis Buckley starts in the front-row alongside Tom McCartney and Rodney Ah You who has three Ireland caps to his name.
Connacht only managed one win in their last six league games but the Dragons haven't won in Galway since 2004. It is imperative that Connacht rekindle the kind of home form that saw the Sportsground become something of a fortress in the first half of last season.
Andrew Trimble gets an immediate opportunity to prove a point to Joe Schmidt when Ulster welcome Ospreys to Kingspan Stadium (7.35).
Ulster's record try-scorer was the most high-profile omission from Schmidt's World Cup squad and he makes up an exciting back three alongside Craig Gilroy who scored 11 league tries last season and Louis Ludik. Peter Nelson starts his first game at out-half, while centres Stuart McCloskey and Luke Marshall will look to impress. Rob Herring captains the side at hooker and Willie Faloon returns after three years with Connacht.
Like Ulster, Ospreys lost out in the semi-finals last season. They have enough quality to ask questions of Ulster but the home side should have enough to get off to a winning start.
Ulster v Ospreys,
Live, BBC 2, 7.35
Leo Cullen may be without 17 internationals for this evening's (7.35) trip to Edinburgh in what his first competitive game in charge of Leinster but he can call upon 11 players who have represented their country.
Michael Bent, Jack Conan, Fergus McFadden, Noel Reid and Isaac Boss were included in the Ireland training squad over the summer and all five are included tonight.
Having not featured in a competitive game since last December, newly-appointed captain Kevin McLaughlin makes a welcome return from injury while alongside him, the highly-rated Dan Leavy makes his first start.
Leinster began their Pro12 campaign with a defeat in Scotland (Glasgow) last season and have only won once in Round 1 in the last seven years. Cullen will be eager to ensure that there isn't a repeat of that this time around as he looks to hit the ground running.
Edinburgh v Leinster,
Live, TG4, 7.35