Bumpers for electronic devices are provided. The bumpers may be formed from a polymer coupled to a housing via a primer. The primer may include a first functional group configured to form a chemical bond with the housing a second functional group configured to form a bond with the polymer. Accordingly, externally-mounted bumpers that do not impinge upon internal space within a housing may be provided. However, the bumpers may be employed for various other purposes. Related portable electronic devices, assemblies, and methods are also provided.