Papua New Guinea (PNG) is one of the most maritime-dependent economies in the Pacific. Its mainland coastline is 5,152 km (3,201 mi). Sea transport is the dominant and often only viable mode for domestic and international trade. PNG recorded a GDP of USD 31.02 billion and merchandise trade of USD 18.24 billion in 2023, with a trade surplus of USD 7.42 billion, largely driven by commodity exports. However, the maritime potential of the country remains under-realised, with transport services exports negligible, liner connectivity weak, and many communities experiencing high logistics costs and unreliable services. Drawing on UNCTAD maritime profiles, World Bank and Asian Development Bank reports, PNG Ports Corporation documents, national policy papers and recent industry commentary, this paper analyses PNG’s maritime trade and development from a systems perspective. It reviews trends in trade flows, fleet composition, port activity, infrastructure investment and governance reforms, and contrasts PNG’s position with that of a global hub such as Singapore. The findings show that PNG’s 15 out of 23 ports operated by PNG Ports handle around 7–10 million tonnes of cargo annually and more than 90% of the country’s international trade, with Lae and Port Moresby/Motukea now ranked in the top 50% of Oceania ports in the World Bank Container Port Performance Index. However, limited hinterland connectivity, low shipping frequency on domestic routes, lack of shipbuilding capacity and a persistent deficit in transport services trade continue to constrain inclusive, sustainable growth. The paper concludes that PNG needs an integrated maritime strategy that combines port modernisation, blue-economy initiatives, coastal shipping reform, human-capital development and climate-resilient infrastructure, aligned with the National Oceans Policy 2020–2030 and the Ports Infrastructure Investment Program.