Episode Two - S3-E2
Visible crew/equipment: When Gavin turns up to Nessa and Dave's caravan and says "hiya," two cameramen are reflected in the car as he moves round it after closing the door.
Episode Six - S3-E6
Factual error: Dave and Nessa's wedding is meant to be on 13th June and at the end supposedly 6 months later Nessa, Gavin and Stacey are sat on the sea wall in beautiful sunshine in summery clothes when it should be middle of December.
Episode Six - S3-E6
Continuity mistake: When Gavin and Smithy are side-by-side on the motorway and talking to each other, when we see Gavin's car there is a green and white lorry behind him in Smithy's lane. When we see Smithy's car, there is a silver saloon directly behind him.
Episode Six - S3-E6
Continuity mistake: When Smithy is driving to Wales for the wedding, the head restraints are missing from the front seat. The next shot is an exterior shot of the car and the head restraints are back in.