The question of the impact of positive radical transformations of small ports in large ports due to the war is not well studied in transport geography. An analysis of the theoretical approach to the positive impact of the development of small ports during a war has enabled me to distinguish two variants of these transformations – a rapid increase in goods traffic and the formation a naval base ultraperipheral in a small port. In both cases, there are the preliminary conditions to achieve them: the location on the seafront to escape the adversary’s effective blockade, direct access to a sea for have free relations with the world, the existence of rail line for goods traffic. Ukrainian ports on the Danube are a good example, becoming the leading ports in terms of traffic in 2022. Local ports in the ultra-periphery were radically transformed in the big ports. Local ports in the ultra-periphery. Before the Russian invasion of 2022, the Ukrainian Danube ports were as very small ports. After the collapse of the communist system, they lost much of their traffic and were deprived of rail access. The soviet Odessa railway was divided. One part came under the control of the self-proclaimed Republic of Transnistria, other was formed Moldavian national railway company and other part was integrated in Odessa regional railway of Ukrainian national railway company – Ukrzaliznytsya. This has since prevented the transport of goods from these ports. There has also been a drastic reduction in the amount of goods that were transported by river to the Danube countries during the Soviet era. As a result, traffic in Ukrainian Danube ports ranks last among the ports of the independent period. What’s more, in 2006 Moldova managed to create a small port on the Danube – Giurgiulești. The Ukrainian Danube ports thus have a competitor that absorbs the majority of Moldovan goods. Before 2022, goods were transported by local roads. Only one road connected the Ukrainian Danube ports to the national network. However, part of this motorway crosses Moldovan territory, which sometimes causes problems with traffic control and the fight against smuggling. Gateways to the world during the blockade. The role of these ports changed radically after the start of the Russian invasion in 2022. They became Ukraine’s only window to the world. This was due to their favorable location on the cross-border river linking the Ukrainian ports with the Romanian port of Constanţa. Ukraine and Moldova have signed an agreement to reactivate rail freight traffic on the border line between the two countries (2022), which has been reconstructed by Ukrzaliznytsya. As a result, new terminals and silos have been built or are under construction, and the traffic in the Danube ports increased rapidly. Since 2022, small ports have become the main sea ports of the country as a result of the Russian invasion. More than half of grain exports in 2022 were loaded in the ports of the Great Odessa, and a quarter of in the Danube ports. New war’s logistics chains have created in new conditions for port operations in Ukraine. For this reason, the operators must radically change their logistics. A regular 50-container train has been launched between Constanţa (Romania) and Reni (Ukraine) in 2022. Maersk has launched new container barge services from Constanța to Reni in 2023, one via the Danube Canal and the other in Romanian territorial waters. United Global Logistics has launched a container vessel service between Constanţa and Izmail in 2022. During the naval blockade, only Viking Alliance container terminal in the port of Reni continues to operate. The port of Constanța will become very important for Ukraine. The uncertain future. The radical changes in the role of the three Ukrainian Danube ports – Reni, Izmail and Ust-Dunaysk – as a result of the actual situation are a good example of contradictory developments: large-scale negative processes have a positive effect at the local level. But what will happen after the war: will these ports maintain the same level of traffic as during the war, or will it return to the previous state?