The Giants announced Monday that Snee and Diehl will replace Jahari Evans and Jonathan Stinchcomb of New Orleans, who will not play in the game because the Saints advanced to the Super Bowl.
The Pro Bowl will be played Sunday in Miami's Sun Life Stadium.
The Giants' linemen will join center Shaun O'Hara and receiver Steve Smith on the NFC squad.
O'Hara was voted to the squad as a reserve, but will now start because Dallas' Andre Gurode pulled out of the game with an injury.
Smith, who set a Giants record with 107 receptions this season, was a first alternate who was added to the team when Arizona's Larry Fitzgerald dropped out with a knee injury.
This is the first time the Giants have had three players from the same position group selected to the Pro Bowl since 1962, when Rosie Brown, Darrell Dess and Ray Wietecha — also a tackle, guard and center — received the honor.
Snee and O'Hara, who played in the game last year, are the Giants' first two-time Pro Bowl offensive linemen since Ron Stone was chosen in 2000 and 2001. This will be the first Pro Bowl appearance for Diehl, who has played in all 119 regular season and postseason games since joining the Giants in 2003.
"It is an awesome accomplishment," Diehl said. "This is what you dream of, not only playing in the Super Bowl, but being able to play in this game. It's an awesome feeling. It is truly an honor to think about all the unbelievable players that have been selected and played in this game before."
O'Hara was thrilled with the additions of Snee and Diehl.
"Obviously, being there with Chris last year was great," O'Hara said. "It is very well deserved for both of them. I know they are both excited about the opportunity. As special as the Pro Bowl is, one of the things that really made it even more special last year was having guys down there that you could experience it with. With the addition of Steve and now with Chris and Dave, it certainly adds to that element."
Dallas coach Wade Phillips will coach the NFC team with Jason Garrett serving as the offensive coordinator.
"You take a look at it (the playbook) before you go to bed," Snee said. "But it is basic stuff, whether it be zone blocking, zone right or zone left. I don't know what Dallas will do. It will be all basic stuff that most people understand having played football for numbers of years."