To change the font of your instant messages:
- Sign in to Skype
- In the menu bar, select Tools > Options
- Click IM & SMS and select IM appearance
- Click Change font
You are given the option to choose which font you would like to use, your font style (regular, bold, oblique or bold oblique) and your font size. When you have selected your font settings, click OK.
Please note: changing your font will only change how instant messages are displayed in your own Skype account. Any messages you send to contacts will be received in the font that they have set for their Skype account.