In the effort to decarbonise shipping, a number of measures can be taken, one of which is to switch from conventional to alternative fuels. However, without an active role for seaports in providing adequate bunkering infrastructure for alternative fuels, these targets may not be achieved. Hence, the aim of this article is threefold: (1) to provide an overview of some of the emerging alternative fuel technologies that are being used or tested for further use in maritime transport, (2) to analyse the bunkering infrastructure in seaports, and (3) to assess the level of advancement of Polish ports in relation to the bunkering of alternative fuels by ships and to explore the ports’ plans in this regard. To achieve these goals, several research methods were applied: a critical literature review, desk-study research, critical and comparative analyses, and semi-structured interviews with representatives of three major Polish seaports. The research showed that the level of advancement of Polish seaports in the construction of bunkering infrastructure for alternative fuels is relatively low, as they are still in the early stages of conversations with their stakeholders identifying which new fuels should be included in their plans. However, with the growing number of LNG-fuelled ships operating worldwide, Polish ports are being forced to prepare for LNG bunkering; however, it is on a small scale for now. They have to make a decision about what type of fuel their bunkering infrastructures should be for, and this constitutes the subject of a great deal of uncertainty. All this is even challenging when taking into account the fact that shipowners are also struggling to choose alternative fuels for their ships. This uncertainty could be reduced through closer cooperation between ports and shipowners, between individual ports, and between ports and other shipping stakeholders. Unfortunately, there is a noticeable lack of cooperation between Polish ports in this regard, as well as with the relevant government departments.