Suit
While Ianto has mostly been shown to wear suits in the TV series, several pieces of extended universe material point to the suits being a kind of mask or armor Ianto uses to protect himself.
Torchwood One
Torchwood One, being an organisation with a much more professional ambiance than Torchwood Three, had a dress code that applied to most employees. This is likely where Ianto got used to wearing suits despite describing himself as “not really a suit kind of bloke” before being hired.
Season 1
Ianto’s season 1 suits were generally in shades of grey. They gave him a very professional but subdued image. They were mainly sourced from Marks and Spencer’s.1
These clothes emphasise the differences between him and the rest of the team. Jack even points out that he “doesn’t need a suit to make coffee”.
Season 2
In season 2, the costume designers started incorporating a lot more color into Ianto’s wardrobe and sourced his clothes from a wider variety of stores such as Zara, Savile Row and Next. 1
Casual clothes
In the TV show, Ianto is only shown wearing casual clothes in two episodes:
- Once in Countrycide, presumably to avoid dirtying an expensive suit,
- And twice in Fragments’s flashbacks while he repeatedly asked Jack for a position in Torchwood Three, though he was wearing a suit on the day he was hired.
There are two Big Finish audio dramas with covers showing him wearing casual clothes:
- The Last Beacon, which is set in the countryside similarly to Countrycide,
- And Blind Summit, which is set before Ianto was even hired into Torchwood One by Yvonne Hartman.
Interestingly, both of those stories were written by Gareth David-Lloyd.