Father Christmas will arrive at the Model Yacht Pond at 15:40, courtesy of the Fire and Rescue Service.
Boatworks+ will be offering free hot chocolate and treats to anyone waiting outside its store.
The parade will start from the Model Yacht Pond, go along Castle Emplacement and the bus terminus and then to Fountain Street, before finishing at the Market Square at 16:45.
Entertainment begins in Market Square at 16:00 hosted by IslandFM with music from The Hope Choir.
After the light switch on, Father Christmas and his elves will carry on their parade through the Arcade, onto the High Street, and down the Pollet.
Late-night shopping nights in town will take place on the 5, 12 and 19 December and there will also be the opportunity to do your Christmas shopping on Sunday 22 December.
There will also be a late night shopping evening on The Bridge on Tuesday 17 December.
Father Christmas will turn the lights on there next Friday, 6 December.