Bed level data are presented from transects at the Tollesbury Managed Realignment site, after the managed breaching of the sea wall in August 1995. Twenty measurements were taken at fixed positions along transects relative to an aluminium bar placed across a pair of permanent wooden posts at either end of each transect. Measurements were made to the nearest millimetre using a ruler. All measurements were made by the data author. Data from the original transects were collected monthly from September 1995 to 1998, bimonthly up to 2000 and then in April and September to 2007. Extra transects were added in April 1999 and data collected at the same frequency. The data were collected investigate if the exposure of the agricultural land to seawater would result in the accumulation of silt. The work was funded by the Department for Environment Food & Rural Affairs (Defra) under the Centre for Ecology & Hydrology (CEH) contract C00356 Full details about this dataset can be found at https://doi.org/10.5285/f9513ece-a913-4774-8808-273dcf7ed0be