The team announced the signing on Thursday night. The Seahawks report for training camp on Friday with the first practice scheduled for Saturday morning.
Bryant had a tryout with the Seahawks during June's minicamp. Coach Pete Carroll said he didn't feel Bryant was in football shape then and wanted to see if the veteran could get himself ready in the month between the June tryout and training camp.
Bryant has not played since the 2009 season with Tampa Bay. He signed a four-year, $28 million with Cincinnati before the 2010 season, but was cut at the end of training camp and spent the past two seasons out of the NFL.
The Seahawks will open training camp with plenty of questions at wide receiver. Sidney Rice is coming off two shoulder surgeries in the offseason and the rest of Seattle's receiving corps is mostly unproven. Seattle released Mike Williams earlier this month.
Free agent wide receiver Braylon Edwards worked out for the Seahawks earlier Thursday.
The 29-year-old Edwards played in nine games last season for San Francisco. He caught 15 passes for 181 yards and no touchdowns during an injury-plagued year that saw him get released by the 49ers in December.
Information from The Associated Press was used in this report.