Abstract: This paper utilizes sea ice density and sea ice thickness data from 1991 to 2021 and the newly released International Maritime Organization (IMO) Polar Operation Limit Assessment Risk Index System (POLARIS) to assess the comprehensive navigational risk value of the middle- and low-latitude routes of the Northeast Arctic shipping lanes using a novel SARIMA-LSTM model. The combined prediction model forecasts medium- and long-term trends in sea ice conditions in the Northeast Arctic Passage, and the navigability of two representative ship types in this region is examined. Compared with the previous 10 years, the sea ice conditions in the Northeast Arctic Fairway show improvement over the 2022–2035, in which the average sea ice density and sea ice thickness are reduced by 11.31% and 4.82%, respectively, with more pronounced changes during summer and autumn. Based on the IMO POLARIS, the comprehensive navigational risk of both IACS PC7 and IACS PC3 ice-class ships is decreasing. The average risk index outcome (RIO) of IACS PC7 ice-class ships in each sea area of the Arctic Northeast Passage during July–December is greater than zero, which indicates that the navigational risk of the ships is controllable, and the ships can be operated normally during this period. The RIO of IACS PC3 is greater than zero throughout the year, the navigational risk of IACS PC3 ice-class ships is controllable over the whole sea area throughout the year, and the ships can be operated normally. Based on the navigation standards set by ship navigation simulations, the future navigable time in the Northeast Arctic Passage varies markedly among the sample ships, with no significant change in the navigable time of IACS PC7 ice-class ships, which remains at August–November, while the period of navigability of IACS PC3 ice-class ships is extended from July–January to June–February.

Key words: Arctic Northeast Passage, ice prediction, seaworthiness, combined SARIMA-LSTM model