Maritime transport is the backbone of the global economy and a critical enabler of modern society [1, 2]. A substantial fraction of international trade in energy, raw materials, manufactured goods, and foodstuffs is carried by sea, supported by a heterogeneous global fleet ranging from large container vessels and tankers to offshore support vessels and specialized service ships. This vast and continuously operating system depends on the ability to navigate safely and efficiently through an ocean environment that is inherently stochastic, multi-scale, and increasingly impacted by climate variability and change. Within this context, sea state estimation (SSE)—the quantitative characterization of ocean surface waves in terms of parameters such as significant wave height, peak period, spectral shape, and directional spreading—plays a foundational role [3–5].