Fly in Fly out/Drive in Drive out (FIFO/DIDO) is a prevalent work arrangement in the Australian mining industry and has been associated with adverse outcomes such as psychological stress, sleep disturbances, fatigue, and work/life interference. FIFO/DIDO work arrangements have the potential to not only impact the FIFO/DIDO worker, but also the partner of the FIFO/DIDO worker. However, there is sparse empirical evidence on the impact of FIFO/DIDO work arrangements on partners’ sleep and subsequent performance. Therefore, the primary aim of this study was to describe and compare partners’ sleep quality, sleep duration, sleepiness, and loneliness when the FIFO/DIDO workers were at home (off-shift) and away (on-shift). A secondary aim of this study was to examine whether differences in partners’ sleep quality and sleep duration as a result of FIFO/DIDO worker’s absence could be partially explained through the presence of dependents in the home, relationship duration, chronotype, duration in a FIFO/DIDO role, and loneliness. Self-reported questionnaires were completed by 195 female and 4 male participants, mostly aged between 18 and 44 years and who had been in a relationship with a FIFO/DIDO mining worker for more than five years. Of note, most participants subjectively reported poor sleep quality, insufficient sleep duration, excessive sleepiness, and moderate to extreme loneliness compared to the general population regardless of whether the FIFO/DIDO workers were at home or away. Compared to when the FIFO/DIDO workers were at home, partners experienced reduced sleep quality and increased loneliness when the FIFO/DIDO workers were away. Secondary analyses revealed that loneliness may partially underpin the negative effect that FIFO/DIDO workers’ absence has on sleep quality. Further research is needed to understand the factors that contribute to poor sleep quality, insufficient sleep duration, excessive sleepiness, and loneliness of FIFO/DIDO partners to inform appropriate strategies to support FIFO/DIDO partners’ health and wellbeing not only in the mining population, but other industries that incorporate similar FIFO/DIDO work arrangements (e.g., emergency services, offshore drilling, and transport).