Another great Nature Reserve [well to me anyway] is The Trimley Marshes again run by The SWT, there is one snag you have at least a mile to walk either from Searsons Farm, Trimley [car park] or from Levington Marina.
We have done both routes many times but prefer the walk from Levington as it takes you past the marina, Loompit Lake [look for the hundreds of Cormorants on the trees and a few egrets], then on a bund around a lagoon to the first of a few hides before you get to the visitors centre.
If you walk along the bund [artificial sea wall] you will be walking adjacent to the River Orwell with fine views and birdlife, you might even catch a glimpse of a Thames Barge.
This view is from edge of the lagoon looking towards Felixstowe Dock.
The reserve hosts many waders and other visitors, it is well worth the effort, there are toilet facilities at the centre and a cafe open at weekends
The most prolific of nature reserves in Suffolk surely must be Minsmere, we visit this reserve quite frequently, if you haven't seen a Marsh Harrier then this is the place to see them or hear a booming Bittern or Cetti Warblers, or see Bearded Tits. I have never been to the bird reserve and seen lass than 50 species of birds in any one day. You will need binoculars and a good strong pair of walking boots, there is a visitor centre, cafe, toilets, book shop on site and is run by The RSPB