Previous work has shown that talking on a mobile phone leads to an impairment of visual attention. Gunnell et al. (2020) investigated the locus of these dual-task impairments and found that although phone conversations led to cognitive delays in response times, other mechanisms underlying particular selective attention tasks were unaffected. Here we investigated which attentional networks, if any, were impaired by having a phone conversation. We used the Attentional Network Task (ANT) to evaluate performance of the alerting, orienting and executive attentional networks, both in conditions where people were engaged in a conversation and where they were silent. Two experiments showed that there was a robust delay in response across all three networks. However, at the individual network level, holding a conversation did not influence the size of the alerting or orienting effects but it did reduce the size of the conflict effect within the executive network. The findings suggest that holding a conversation can reduce the overall speed of responding and, via its influence on the executive network, can reduce the amount of information that can be processed from the environment