The smaller, more remote of the two lake groups lies about 40 km southeast of Ounianga Kébir, reachable only by 4WD across rough desert terrain. The piste is not marked and requires a guide who knows the route.
Ounianga Sérir contains roughly eight lakes, several of them partially covered by floating mats of reeds and aquatic vegetation. The reed mats act as a natural sunshade, dramatically reducing evaporation from the lake surface — which is how these smaller, shallower lakes survive in an environment where they would otherwise disappear entirely within decades. The mats are dense enough in places to walk on, and local herders have used them as dry-season pasture.
Several of the Sérir lakes are nearly circular, cupped in depressions between dune ridges, and the effect from higher ground is of gemstones dropped into sand. The water ranges from clear freshwater to brine dense enough to keep a person effortlessly afloat. Some lakes are too saline for fish but support dense colonies of brine shrimp and the migratory birds that feed on them.
There is nothing at Ounianga Sérir in the way of facilities. Visitors camp beside the lakes. The isolation is absolute — no villages, no tracks beyond the route in, no means of communication if something goes wrong.