There's a sidewalk from Terminal A arrivals that you can take to the Maverick neighborhood and the East Boston Greenway. There was one from Terminal E as well t

There's a sidewalk from Terminal A arrivals that you can take to the Maverick neighborhood and the East Boston Greenway. There was one from Terminal E as well to Wood Island and beyond, but part of it's been closed for a while due to the Terminal E expansion. There's a pedestrian detour through the cell phone lot that'll get you there. You won't be able to walk to Downtown Boston, obviously, but Logan Airport is theoretically walkable if you're in East Boston. I'd still take the shuttle bus to the Airport T station where you can do the same walk to the greenway.