Despite years of research, the glycomes of invertebrates continue to surprise. Gone are the days when it could be said that “simple” organisms have “simple” glycomes. Typically, any biological sample will yield a complex mixture of 100 N-glycans or more, whereby low-abundance structures are still underestimated. On the other hand, as there are variations in structures or abundance of glycoconjugates between species, it appears that speciation correlates with glycomic alterations and thereby with the evolution of special ecological niches, such as being parasites which infect hosts and are transmitted through other invertebrates. This also means that the glycome of each parasitic and host species may act as a “passport” to allow infection or transmission, which leads to the question of which glycans can bind which receptors. In our recent studies on parasites and vectors, as well as comparisons to related species, we see potential for glycomimickry as being a factor. For instance, the canine heartworm Dirofilaria immitis is transmitted by the mosquito Aedes aegypti; both display glucuronic acid modifications of their N-glycans. On the other hand, the heartworm also expresses phosphorylcholine-modified structures which, as shown by glycan array experiments, can interact with mammalian C-reactive protein. Overall, the heartworm N-glycome contrasts with those reported to date for other parasitic nematodes. For instance, neither Trichuris suis, Haemonchus contortus nor Oesophagostomum dentatum have glucuronylated N-glycans, which are all gut parasites, but the latter two have trifucosylated core chitobiose modifications found neither in Trichuris suis or Dirofilaria immitis. This leads us to wonder about the functional repercussions of these variations and whether parasite tropism (in terms of vector, host and tissue) and mode of immunomodulation is affected by glycan structures. Thereby, a mix of approaches including in depth glycomics, glycan arrays, glycoenzymology and chemoenzymatic synthesis are key to informing parasitological, vaccinological and immunological studies.