If you have lost something at a Thameslink station or onboard a Thameslink train, please visit the Thameslink Website and use the webform to register your lost item.
Some Thameslink trains serve stations which are managed by other train operators (see below). You should consider logging your lost item with them, just in case it's been handed in at one of their stations.
If you have found an item of lost property, please hand it in to a member of staff.