Starting from the waterfront
Coast Road is a useful starting point for a walk that returns through the town. The harbour, Old City and beach provide easy-to-identify landmarks, but the northern marsh is reached by a different mix of roads and signed paths.
The Strood Channel side
The northern shore looks across saltmarsh, Ray Island and the channel leading towards the Strood. Keep to signed rights of way: not every sea wall or field boundary is public, and soft mud is not a walkable alternative.
Making the loop
The commonly quoted nine-kilometre figure is an approximate length for a published West Mersea circuit, not a surveyed distance for every variation. Check the Essex rights of way map before choosing the inland link back to the south shore. Road sections may have no pavement.
An easier alternative
For a shorter trip without remote paths, stay with the waterfront and town streets. For a much longer outing, the island circuit is a separate, full-day undertaking.