Bumblebees, Bombus (Hymenoptera) are associated with a broad variety of phoretic mites, with the most studied species belonging to the genera Parasitellus (Mesostigmata: Parasitidae), Scutacarus (Prostigmata: Scutacaridae), and Kuzinia (Astigmata: Acaridae). In a first-of-its-kind study on the diversity of phoretic mites of Bombus populations of the hills bordering Snowdonia Mountains, North Wales, we identified a large variety of morpho-species of Bombus phoretic mites, previously unknown for the UK and most of Europe. Preliminary analyses of the dynamics of Bombus-Acari associations showed rare patterns of interaction. As an example, Laelapidae were more numerous and prevalent than the expected Parasitidae. The novelty of the findings will be discussed in relation to the particular environmental conditions of this pristine location. This is an area consistently isolated from the frequent releases (from populations abroad) of Bombus terrestris for pollinator services. The study allowed us to know and understand this endemic fauna of the hills of North Wales.