The Seattle Seahawks beat the Denver Broncos in the Super Bowl. They won Super Bowl XLVIII after the 2013 season, defeating the Denver Broncos 43–8 in one of the most lopsided Super Bowls in NFL history.

So, if you’re just looking to settle a quick debate: the Seahawks’ Super Bowl win came against the Denver Broncos.

TL;DR: Seahawks’ lone Super Bowl victory = vs. Denver Broncos, 43–8, in Super Bowl XLVIII.

Information gathered from public forums or data available on the internet and portrayed here.