Fishing for rainbow trout, kokanee salmon and perch should be good because the fish have not been disturbed since the lake froze over a few weeks ago. Anglers are advised to protect themselves against the harsh elements by choosing clothing that provides protection from low air temperatures, wind and precipitation while at the same time allowing mobility. Also keep in mind the possibility of falling through the ice. Clothing that would severely restrict your ability to swim or to stay afloat is not a good choice. Hip boots or waders should never be worn, as they can fill with water and restrict movement. A personal flotation device should be worn. This can be a vest or jacket, either inflatable or naturally buoyant.

Snowmobiles and all-terrain vehicles are allowed on the ice, but not on the state park shorelines. All vehicles must be taken into the park on trailers and driven directly onto the ice from the boat ramp. Ice fishing access to the lake is available through the state park for a $5 per vehicle day-use fee, or free of charge through the park's three designated free access points.

The State Parks Division and the Department of Game and Fish jointly manage Eagle Nest Lake and surroundings via a Joint Powers Agreement. According to criteria established by both agencies under the agreement, Eagle Nest Lake State Park staff report the ice conditions to the Department of Game and Fish. When the ice thickness meets its requirements, the Department allows ice fishing on the lake. The Department of Game and Fish has the authority to open or close the lake to ice fishing. State Parks assists with the on-the-ground posting and enforcement of the ice-fishing determinations. In addition, State Park managers and superintendents have the authority, by regulation, to close or restrict access to areas of parks, as well as to restrict, limit or prohibit activities such as ice fishing as conditions require. Such actions are taken in the interest of public safety and resource protection.

The State Parks Division has a formal procedure for checking the depth of ice. The ice thickness is measured starting at the shoreline and progressing out over the lake. When the ice is of a thickness that is considered safe, the lake is opened to ice fishing. Also, park staff continually makes visual checks of the ice looking for cracks, water on top of the ice, and open water, all signs that the ice may not be safe for anglers.