In 2020, Callum won the bid to serve as Switzerland Tourism's lead photographer for their North American marketing campaign; spending two weeks on location capturing assets for the tourism board and five of its regional partners, and, the Swiss Travel System, Mammut, and Victorinox.

The project also supported Switzerland's post-COVID tourism recovery, with Callum sharing the work across his social platforms to an audience built to care about exactly this kind of travel. Switzerland Tourism returned to purchase additional imagery before the project had even closed. This marks the fourth project Callum has worked on with Switzerland Tourism.