2021 Seattle Seahawks season

The 2021 season was the Seattle Seahawks' 46th season in the National Football League (NFL), their 20th playing their home games at their current venue, Lumen Field, as well as their 12th under head coach Pete Carroll.

The Seahawks failed to improve on the previous year's 12–4 record after their Week 7 loss to the New Orleans Saints, and after their 10–20 loss to division rival Los Angeles Rams in Week 15, the Seahawks suffered their first losing season since 2011, and their only losing season of the Russell Wilson era. Following their Week 16 loss to the Chicago Bears, the Seahawks suffered their first double-digit losing season since 2009, finished last in their division for the first time since 1996, when they played in the AFC West, and were eliminated from playoff contention for the first time since 2017.

The Seahawks continued to struggle defensively from the previous year, ranking dead last in total yards allowed, giving up a total of 2,254 yards in the first five games of season and were on pace to give up the most yards in a season in NFL history for the second straight year. Overall, the Seahawks allowed 6,445 yards, or 379.1 per game. Quarterback Russell Wilson also missed a game for the first time in his NFL career, missing three games after injuring his middle finger in Week 5 against the Rams.

This was the first season since 2010 without longtime linebacker K. J. Wright, who signed with the Las Vegas Raiders on September 6, 2021. It was also the last season with Russell Wilson on the roster and the final season of linebacker Bobby Wagner's first stint with the team. Wagner was released on March 9, 2022, and signed a five-year contract worth up to $65 million with the defending Super Bowl LVI champion Los Angeles Rams on March 31 before being cut and returning to the Seahawks the next season, while Wilson was traded to the Denver Broncos along with a 4th round pick for quarterback Drew Lock, defensive lineman Shelby Harris, tight end Noah Fant, two first-round picks, two second-round picks and a fifth round pick on March 16. Both were the last remaining members from their 2013 Super Bowl-winning season on the roster.

Draft
Notes
 * The Seahawks traded safety Bradley McDougald, first- and third-round selections, and a 2022 first-round selection to the New York Jets in exchange for Jamal Adams and a 2022 fourth-round selection.
 * The Seahawks traded their fourth-round selection (No. 129) to the Tampa Bay Buccaneers in exchange for the Buccaneers' fourth-round selection (No. 137) and a sixth-round compensatory selection (No. 217).
 * The Seahawks traded their fifth-round selection to the Las Vegas Raiders in exchange for offensive guard Gabe Jackson.
 * The Seahawks traded a sixth-round selection to the Miami Dolphins in exchange for a 2020 seventh-round selection. This selection was traded to the Chicago Bears. The Bears traded this selection back to the Seahawks in exchange for a sixth-round selection (No. 217), originally from the Tampa Bay Buccaneers, and the Seahawks' seventh-round selection (No. 250).
 * The Seahawks received safety Quandre Diggs and a seventh-round selection from the Detroit Lions in exchange for a 2020 fifth-round selection.
 * The Seahawks traded center B. J. Finney and the Detroit Lions's seventh-round selection to Cincinnati Bengals for defensive end Carlos Dunlap.

Preseason
The Seahawks' preseason schedule was announced on May 12.

Schedule
The Seahawks' regular season schedule was announced on May 12.

Divisional matchups: the NFC West played the NFC North and the AFC South.

Note: Intra-division opponents are in bold text.

Week 3: at Minnesota Vikings
This was Seattle's first loss to the Vikings since 2009.

Week 10: at Green Bay Packers
This was the first time the Seahawks were shutout in a game since Week 2 of the 2011 against the Pittsburgh Steelers. Russell Wilson return from finger injury.

Week 16: vs. Chicago Bears
With the loss, the Seahawks were eliminated from the playoff contention for the first time since 2017.

Week 18: at Arizona Cardinals
This game was Russell Wilson's last as a quarterback for the Seahawks before he was traded to the Denver Broncos the following offseason.