Jenkins will win his 102nd Wales cap at the Aviva Stadium, lining up in the front row alongside Ospreys duo Richard Hibbard and Adam Jones.
Coombs, who made his debut against Ireland twelve months ago, replaces Luke Charteris who is ruled out with a hamstring injury. His second row partner will be Alun Wyn Jones who led Wales to their opening round win in Cardiff.
Warburton, who featured off the bench against the Azzurri, starts at openside flanker alongside Dan Lydiate and Toby Faletau.
Since making his Six Nations debut at the Aviva Stadium in 2012, Faletau has started every match in the tournament for Wales.
The back-line remains unchanged for the trip across the Irish sea, with 25-year-old full-back Leigh Halfpenny winning his 50th cap for his country.
He again lines up in the back-three alongside Alex Cuthbert and George North, the trio combining for a 12th straight time in the Six Nations.
Scott Williams, a try scorer against Italy, and Jamie Roberts continue their partnership in the midfield, with Rhys Priestland and Mike Phillips featuring once more at half-back.
Head coach Warren Gatland said: "It's great to bring Sam and Gethin back into the side and it's a good opportunity for Andrew Coombs to start as well.
"Last weekend was a good hit-out for a lot of reasons, but we still have things to work on and we know how important this game is.
"We haven't lost an away match in the Six Nations since 2011 and we have to have the belief and confidence that we can do it again this weekend.
"It's going to be tough, both sides won their opening game, we will have to be physical and take it to them.
"We feel in most tournaments we get stronger as it goes on and that will need to be the case this weekend."
WALES Team & Replacements (v Ireland, 2014 RBS 6 Nations Championship, Aviva Stadium, Saturday, February 8, kick-off 2.30pm):
15 - Leigh Halfpenny (Cardiff Blues) 49
14 - Alex Cuthbert (Cardiff Blues) 20
13 - Scott Williams (Scarlets) 24
12 - Jamie Roberts (Racing Metro 92) 54
11 - George North (Northampton Saints) 36
10 - Rhys Priestland (Scarlets) 26
9 - Mike Phillips (Racing Metro 92) 81
1 - Gethin Jenkins (Cardiff Blues) 101
2 - Richard Hibbard (Ospreys) 27
3 - Adam Jones (Ospreys) 90
4 - Andrew Coombs (Newport Gwent Dragons) 7
5 - Alun Wyn Jones (Ospreys) 75
6 - Dan Lydiate (Racing Metro 92) 31
7 - Sam Warburton (Cardiff Blues) 42 (capt)
8 - Toby Faletau (Newport Gwent Dragons) 30
16 - Ken Owens (Scarlets) 20
17 - Paul James (Bath) 49
18 - Rhodri Jones (Scarlets) 6
19 - Jake Ball (Scarlets) *
20 - Justin Tipuric (Ospreys) 20
21 - Rhys Webb (Ospreys) 4
22 - James Hook (Perpignan) 73
23 - Liam Williams (Scarlets) 8
* Denotes uncapped player