Background <p>Antenatal care (ANC) provides an opportunity to prevent or minimise adverse pregnancy outcomes and enhance women’s health by providing essential interventions including malaria prevention measures. In Papua New Guinea (PNG), three quarters of women commence ANC after the first trimester of pregnancy and one in five women receive no ANC. The present qualitative study aimed to explore determinants of ANC utilisation in the context of a clinical trial of intermittent preventative treatment of malaria in pregnancy in PNG.</p> Methods <p>A cross-sectional qualitative study was conducted at four health facilities in Madang Province, PNG, between 17 April and 6 September 2023. Data were collected through individual in-depth interviews, focus group discussions (FGDs) and observations of ANC proceedings at clinics. Study participants included 79 pregnant and 5 postpartum women, 15 healthcare providers, and 13 representatives of district, provincial and national health authorities involved with the programming of ANC. In-depth interviews and FGDs were audio-recorded and transcribed. Transcript data were coded using deductive and inductive approaches. Emerging themes from interviews and FGDs were triangulated with data from field notes and observations.</p> Results <p>We identified four main themes in relation to ANC utilisation: accessibility of ANC; attitudes towards ANC; interpersonal factors; and timing of ANC. Accessibility of ANC services related to costs associated with ANC, healthcare service delivery challenges, proximity to clinics, and rigid clinic schedules. Attitudes toward ANC, including the perceived benefits and disadvantages, knowledge of ANC interventions and access to education, influenced utilisation. In terms of interpersonal factors, positive relationships and communication between women and healthcare providers, and community or family members participation, were enablers of ANC engagement, while negative healthcare provider attitudes and fear of pregnancy disclosure were identified as potential barriers. Timing of ANC contacts were influenced by personal choice, a desire to avoid many clinic visits, community attitudes, prior pregnancy experiences, distance to health facilities, anticipated travel and clinic costs, attitudes of community members around ANC timing and lack of awareness of pregnancy or gestational age. Most women considered ANC important and recognised the need for ANC to ensure safe pregnancy and delivery.</p> Conclusions <p>Healthcare benefits of ANC were perceived as an important part of ensuring a safe pregnancy and delivery outcome. ANC initiation and utilisation were enhanced through clinic fee remission, ANC content, and community engagement provided in the context of a clinical trial. These findings highlight opportunities for strategic programmatic investments that could lead to improved ANC utilisation in Madang Province.</p>