The M48 Severn Bridge will be closed in one direction overnight on Tuesday as work to remove the tolls continues.
The bridge will also be closed between 07:00 BST and 19:00 on Sunday 28 April.
Motorists travelling from England to Wales have been advised to use the M4 Prince of Wales Bridge instead.
Highways England said Tuesday night's closure would enable traffic diversions to be set up, which would be in place for eight weeks while the works were completed.
Traffic will be diverted off the M48 at the junction one exit slip road and return via the entry slip road.
Engineers will be resurfacing the road, realigning the carriageway and slip road and upgrading the kerbs, drainage system and safety fencing.
"We understand that this will have an impact on drivers and apologise in advance for any inconvenience this may cause," said Hannah Milliner, of Highways England.