Isa'ako "Isaac" Sopoaga (pronounced /soʊpoʊˈɑːɡə/ soh-poh-AH-gə; born September 4, 1981) is a former American football nose tackle.

[4] He then attended the University of Hawaii, where he started his junior and senior years, and collected 128 tackles (70 solos) with four sacks for minus 28 yards, 15 stops for losses of 56 yards, eleven quarterback pressures, a pair of fumble recoveries, two forced fumbles and three pass deflections in 25 games with the Warriors.

[6] As of 2018[update], Sopoaga is one of only seventeen prospects to repeat more than 40 lifts at the 225-pound (102 kg) bench press at the NFL Scouting Combine since 1999.

While he was noted for his "outstanding strength" and quickness off the snap, scouts criticized his tendency to "get tall, which negates his power," as well as his lack of hand technique.

In a Monday press conference following the game 49ers head coach Mike Singletary said that putting Sopoaga in as fullback was an idea he presented to former offensive coordinator Jimmy Raye earlier in 2010.

Singletary gave credit to Bill Walsh's playing of guard Guy McIntyre as a fullback rather than Mike Ditka's playing of lineman William "The Fridge" Perry as a fullback on Singletary's Chicago Bears team, since Walsh started the trend and Ditka followed.

On October 30, 2011, playing from fullback position, Sopoaga caught a pass for a key first down in the fourth quarter of the 49ers' 20–10 victory over the Cleveland Browns.

[18] Sopoaga's nephew, Penei Sewell, won the Outland and Morris trophies playing college football for the Oregon Ducks and is an All-Pro and 2× Pro Bowl offensive tackle taken 7th overall by the Detroit Lions in the 2021 NFL draft.