The 49ers can't announce the signing until Friday. Akers told The Associated Press it's for three years.
Akers is coming off consecutive Pro Bowl seasons, and showed no signs of slowing down last year — he set a career high with 23 touchbacks. But the Eagles drafted kicker Alex Henery in the fourth round, making Akers expendable.
Philadelphia had placed the transition tag on Akers before the NFL lockout, but that became invalid.
Akers has connected on 81.9 percent of his field goals and 98.7 percent of his extra points. He was cut by three different teams before signing with the Eagles in 1999.
Akers went on to set the franchise record for points, field goals, extra points, games played in the regular season and in the playoffs. He was selected to the NFL's All-Decade team for the 2000s, and only Morten Andersen (seven) and Jan Stenerud (six) have made more Pro Bowls.