Optimization of the ship route in ice-covered waters improves the efficiency and safety of navigation in the Arctic. This article describes a new wave-based approach for ice routing of a ship. Unlike grid-based approaches, which use a predefined grid to describe possible ship movements, the proposed algorithm is cell-free and extends the method of isochrones. All calculations of isochrone propagation are done using geo-algorithms and operations with geo-polygons. This allows us to use a standard vector ice data in its initial form, as well as to consider such special features as the discontinuities in ice cover, ice leads, and fractures.