According to the Biological Species Concept, reproductive isolation defines populations; through ecological, adaptive, and mechanistic barriers to gene flow. Introducing variation alongside mutation, recombination challenges the notion of bacterial asexuality. A predominant mechanistic barrier to recombination is sequence identity; yet up to 23% of the Campylobacter coli core genome contains Campylobacter jejuni DNA despite their 85% Average Nucleotide Identity (ANI).   Our findings predict that C. coli has a lower reliance on sequence homology for introgression. Homologous sequence lengths of 74 nucleotides are optimal for RecA-mediated recombination in Escherichia coli, yet there is no enrichment of homologous 74-mers in regions of recombination in C. coli. Instead, shorter homologous K-mers were observed in recombination hotspots.  Mutation rates are high in Campylobacter due to a lack of DNA mismatch repair, so relaxed mechanistic barriers for recombination could increase gene flow and prevent deleterious mutation accumulation, avoiding Muller’s Ratchet. Simultaneously, introducing variation this way could offset the ecological genetic isolation of host-restricted niches. This aligns with the elevated introgression between Campylobacter species, when ecological barriers are weakened, for example when host niches overlap. With agricultural intensification, this is becoming an increasingly prevalent scenario, so understanding of gene flow barriers and speciation can inform trait acquisition predictions, such as Antimicrobial Resistance.