Bell, 34, signed a one-year, $1.4 million deal, according to a source. It includes a $1.1 million base salary, which is guaranteed, plus a $200,000 signing bonus and a $100,000 workout bonus.
Bell and Landry are expected to be the starting safeties, with Eric Smith coming off the bench.
Bell's arrival could mean the end of Jim Leonhard's three-year run with the Jets. The popular Leonhard is an unrestricted free agent, five months removed from major knee surgery, but there has been mutual interest in a return -- assuming he gets healthy.
"We hope Jim can come back, we really do," cornerback Darrelle Revis said Wednesday, referring to Leonhard as the "quarterback" of the secondary.
One variable could be Landry's health. He's still rehabbing an Achilles injury from last season and hasn't been able to participate in the practices during voluntary workouts.
The team expects him to be ready by the regular season, but there's obvious concern because his one-year, $3.5 million contract is based heavily on playing-time bonuses.
Bell, 6-foot, 205 pounds, is an in-the-box safety. He recorded a team-high 107 tackles last season for the Dolphins, the fourth straight year he led the team. He also had one interception and two sacks.
The Dolphins released Bell in a salary-cap move. He worked out for the Philadelphia Eagles, Kansas City Chiefs, Tennessee Titans and the Jets, whose offensive coordinator -- Tony Sparano -- was the Dolphins' coach from 2008-11.