Castletown square is now open for car parking.
The square has been closed to traffic since last summer when the regeneration scheme – involving new paving and lighting - began.
Its reopening is in line with when the scheme was scheduled to finish.
Commissioners’ chairman Alwyn Collister said: ‘We will be having an official opening later on. There are still little things that need to be finished off.
‘I’m pleased to see it finished. It looks nice at night, when it is all lit up. Some of the buildings are floodlit, some others have yet to be done.’