Systems and methods for suppressing magnetically active surface defects in superconducting quantum circuits are provided. A method includes providing one or more superconducting quantum circuits, and arranging the one or more superconducting quantum circuits in a hermetic enclosure capable of isolating the one or more superconducting circuits from ambient surroundings. The method also includes controlling an environment in the hermetic enclosure to suppress magnetically active surface defects associated with the one or more superconducting quantum circuits. In some aspects, the method further includes introducing an inert gas into the hermetic enclosure to passivate a surface of the one or more superconducting quantum circuits. In other aspects, the method further includes coating a surface of the one or more superconducting circuits with a non-magnetic encapsulation layer. In yet other aspects, the method further includes irradiating the one or more superconducting circuits using ultraviolet light.