Trimley Marshes is a 77 hectare nature reserve west of Trimley St Mary, on the outskirts of Felixstowe in Suffolk.

[1] It is in the Suffolk Coast and Heaths Area of Outstanding Natural Beauty,[2] the Orwell Estuary Site of Special Scientific Interest,[3] the Stour and Orwell Estuaries Ramsar site internationally important wetland site[4][5] and Special Protection Area under the European Union Directive on the Conservation of Wild Birds.

[6][7] This site has a reservoir, islands, reedbeds and marshes.

It has a rich variety and number of birds, such as redshankss, avocets, oystercatchers, little grebes and gadwalls.

[1] There is access to the site from Cordy's Lane.