Water Classification for Lakes and Oceans
Learn about the various water classifications we use for lakes and ocean environments.
We have a dedicated page for water classifications specifically for river environments.
Class-0
Environment: Non-challenging protected waters with limited wind effect, little or no current, easy landings, and ready access to land-based assistance. Wind and sea state is calm to rippled (<15km/h or 8 knots).
Class-1
Environment: Non-challenging waters with mild wind effect (0-20 km/h or 0–11 knots), little or no current (0-1 km/h or 0–0.5 knots), uninterrupted easy landing options, and ready access to land-based assistance. Sea state is calm to light chop.
Class-2
Environment: Moderately exposed coastline with frequent easy-landing opportunities and short crossings. Moderate potential wind effects (22-35 km/h or 12–19 knots), surf of less than 1 meter and a combined sea state of less than 1 metre, gentle to moderate non-turbulent currents (< 6 km/h or < 3 knots), and light surf beaches. Short delays in access to land-based assistance should be expected.
Class-3
Environment: Exposed water, with more committed crossings and any combination of the following: moderate to strong currents with turbulence (≥ 6 km/h or ≥ 3 knots), moderate to strong wind effects (22-35 km/h or 12–19 knots), ocean swells and a combined sea state near 1 meter with occasional rough sea state. Difficult but frequent landing opportunities, surf-beaches with surf up to 1 metre. Delays in access to land-based assistance can expected.
Class-4
Environment: Rugged and exposed coast with long and committed crossings and any combination of the following: strong turbulent currents (≥ 6 km/h or ≥ 3 knots), strong wind effects (near 37 km/h or 20 knots), large swells with a combined sea state 1 metre or more with a moderate to rough sea state, exposed surf beaches (≥1 metre), infrequent and sometimes difficult landings which present significant challenges for individual safety and group management. Significant delays in access to land-based assistance can be expected.
Last updated: April 11, 2026
Published: January 2, 2025
